JP4120600B2 - Method for manufacturing light emitting device - Google Patents

Method for manufacturing light emitting device Download PDF

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JP4120600B2
JP4120600B2 JP2004052360A JP2004052360A JP4120600B2 JP 4120600 B2 JP4120600 B2 JP 4120600B2 JP 2004052360 A JP2004052360 A JP 2004052360A JP 2004052360 A JP2004052360 A JP 2004052360A JP 4120600 B2 JP4120600 B2 JP 4120600B2
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light emitting
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JP2005243954A (en
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雅人 山田
雅宣 高橋
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Shin Etsu Handotai Co Ltd
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Description

この発明は発光素子の製造方法に関する。 This invention relates to a method of manufacturing a light emitting device.

特開２００１−３３９１００号公報JP 2001-339100 A 日経エレクトロニクス２００２年１０月２１日号１２４頁〜１３２頁Nikkei Electronics October 21, 2002, pages 124-132

発光ダイオードや半導体レーザー等の発光素子に使用される材料及び素子構造は、長年にわたる進歩の結果、素子内部における光電変換効率が理論上の限界に次第に近づきつつある。従って、一層高輝度の素子を得ようとした場合、素子からの光取出し効率が極めて重要となる。例えば、ＡｌＧａＩｎＰ混晶により発光層部が形成された発光素子は、薄いＡｌＧａＩｎＰ（あるいはＧａＩｎＰ）活性層を、それよりもバンドギャップの大きいｎ型ＡｌＧａＩｎＰクラッド層とｐ型ＡｌＧａＩｎＰクラッド層とによりサンドイッチ状に挟んだダブルへテロ構造を採用することにより、高輝度の素子を実現できる。このようなＡｌＧａＩｎＰダブルへテロ構造は、ＡｌＧａＩｎＰ混晶がＧａＡｓと格子整合することを利用して、ＧａＡｓ単結晶基板上にＡｌＧａＩｎＰ混晶からなる各層をエピタキシャル成長させることにより形成できる。そして、これを発光素子として利用する際には、通常、ＧａＡｓ単結晶基板（以下、単にＧａＡｓ基板ということがある）をそのまま素子基板として利用することも多い。しかしながら、発光層部を構成するＡｌＧａＩｎＰ混晶はＧａＡｓよりもバンドギャップが大きいため、発光した光が素子基板部に吸収されて十分な光取出し効率が得られにくい難点がある。   As a result of many years of progress in materials and element structures used in light-emitting elements such as light-emitting diodes and semiconductor lasers, the photoelectric conversion efficiency inside the elements is gradually approaching the theoretical limit. Therefore, when an element with higher luminance is to be obtained, the light extraction efficiency from the element is extremely important. For example, in a light emitting device having a light emitting layer portion formed of AlGaInP mixed crystal, a thin AlGaInP (or GaInP) active layer is sandwiched between an n-type AlGaInP cladding layer and a p-type AlGaInP cladding layer having a larger band gap. By adopting a sandwiched double hetero structure, a high-luminance element can be realized. Such an AlGaInP double heterostructure can be formed by epitaxially growing each layer of an AlGaInP mixed crystal on a GaAs single crystal substrate by utilizing the lattice matching of the AlGaInP mixed crystal with GaAs. When this is used as a light emitting element, a GaAs single crystal substrate (hereinafter sometimes simply referred to as a GaAs substrate) is often used as it is as an element substrate. However, since the AlGaInP mixed crystal constituting the light emitting layer has a larger band gap than GaAs, the emitted light is absorbed by the element substrate and it is difficult to obtain sufficient light extraction efficiency.

そこで、特許文献１には、成長用のＧａＡｓ基板を剥離する一方、補強用の素子基板（導電性を有するもの）を、反射用のＡｕ層を介して剥離面に貼り合わせる技術が開示されている。また、非特許文献１には、反射率の波長依存性がＡｕよりも小さいＡｌにて反射層を構成することにより、反射強度を高めるようにした発光素子が開示されている。該非特許文献１の素子構造においては、発光層部とシリコン基板からなる素子基板との間にＡｌ反射層が配置され、さらに、Ａｌ反射層とシリコン基板との間には、シリコン基板と発光層部との貼り合わせ接合を容易にするために、Ａｕ層を介在させている。具体的には、発光層部側に形成したＡｌ反射層を覆うようにＡｕ層を形成し、他方シリコン基板側にもＡｕ層を形成して、それらＡｕ層同士を密着させて貼り合わせを行なうようにしている。   Therefore, Patent Document 1 discloses a technique in which a growth GaAs substrate is peeled off while a reinforcing element substrate (having conductivity) is bonded to a peeled surface through a reflective Au layer. Yes. Non-Patent Document 1 discloses a light-emitting element in which the reflection intensity is increased by forming a reflective layer with Al whose wavelength dependency of reflectance is smaller than that of Au. In the element structure of Non-Patent Document 1, an Al reflective layer is disposed between a light emitting layer portion and an element substrate made of a silicon substrate, and further, a silicon substrate and a light emitting layer are disposed between the Al reflective layer and the silicon substrate. In order to facilitate the bonding and bonding with the part, an Au layer is interposed. Specifically, an Au layer is formed so as to cover the Al reflective layer formed on the light emitting layer side, and an Au layer is also formed on the other silicon substrate side, and the Au layers are adhered to each other and bonded together. Like that.

特許文献１及び非特許文献１は、いずれも発光素子の光取出し効率の向上を図る観点において、光吸収性のＧａＡｓ基板は「百害あって一利なし」の技術思想に立脚しており、ＧａＡｓ基板を完全除去することに主眼が置かれている。シリコン基板などと比較すればかなり高価なＧａＡｓ基板を、何ら利用の考慮もなく全て除去し、別に補強用のシリコン基板を設けるというのは、光取出し効率を優先させるためとはいえ、いかにも無駄が多すぎるといえる。また、発光層部成長用のＧａＡｓ基板は、素子製造時に必要なハンドリングのための強度を担う役割も有するのであるが、これを除去すれば、ごく薄い発光層部のみでハンドリング等に耐えうる強度を到底確保できるはずもない。従って、上記文献では、ＧａＡｓ基板を発光層部から除去したあと、Ａｕ層を介してシリコン基板を発光層部に貼り合わせ、このシリコン基板をＧａＡｓ基板に代わる補強用の基板として利用するのであるが、新たな基板の貼り合わせ工程が必要となる。   Both Patent Document 1 and Non-Patent Document 1 are based on the technical idea that a light-absorbing GaAs substrate is “no harm and no advantage” in terms of improving the light extraction efficiency of the light-emitting element. The main focus is on removing the substrate completely. Removing all GaAs substrates, which are quite expensive compared to silicon substrates, without considering any use, and providing a separate silicon substrate for reinforcement, in order to prioritize the light extraction efficiency, is very wasteful. Too many. In addition, the GaAs substrate for the growth of the light emitting layer also has a role of handling strength necessary for manufacturing the device, but if this is removed, the strength that can withstand handling etc. with only a very thin light emitting layer portion. There is no way we can ensure it. Therefore, in the above document, after removing the GaAs substrate from the light emitting layer portion, the silicon substrate is bonded to the light emitting layer portion through the Au layer, and this silicon substrate is used as a reinforcing substrate in place of the GaAs substrate. A new substrate bonding process is required.

本発明の課題は、これまで全面的に除去されていた発光層部成長用のＧａＡｓ基単結晶を、機能的素子構成要素として有効利用することができ、しかも、発光光束の外部への取出し効率も高めることができる発光素子の製造方法を提供することにある。 The object of the present invention is to make effective use of a GaAs-based single crystal for growth of a light-emitting layer part, which has been completely removed so far, as a functional element component, and to take out the luminous flux to the outside. it is to provide a method of fabricating a light emitting device can also increase.

課題を解決するための手段及び発明の効果Means for Solving the Problems and Effects of the Invention

本発明の適用対象となる発光素子は、 ＧａＡｓ単結晶からなる基板本体部の主表面に、ＧａＡｓと異なる組成のＩＩＩ−Ｖ族化合物半導体単結晶からなる分離用化合物半導体層をエピタキシャル成長し、該分離用化合物半導体層上にＧａＡｓ単結晶からなる副基板部をエピタキシャル成長することにより複合成長用基板を作成し副基板部の主表面上に発光層部を有した主化合物半導体層をエピタキシャル成長し、さらに分離用化合物半導体層を化学エッチングにて除去することにより複合成長用基板から副基板部が分離されて主化合物半導体層の主裏面上への残留基板部となるとともに、該残留基板部の一部が切り欠かれて形成された切欠き部の底面が、発光層部からの発光光束に対する光取出面又は反射面とされるものである。 The light emitting device to which the present invention is applied includes epitaxial growth of a separating compound semiconductor layer made of a III-V group compound semiconductor single crystal having a composition different from that of GaAs on the main surface of a substrate main body made of GaAs single crystal, and the separation A substrate for compound growth is produced by epitaxially growing a sub-substrate portion made of GaAs single crystal on the compound semiconductor layer for use, and a main compound semiconductor layer having a light-emitting layer portion is epitaxially grown on the main surface of the sub-substrate portion and further separated. By removing the compound semiconductor layer by chemical etching, the sub-substrate part is separated from the compound growth substrate to become a residual substrate part on the main back surface of the main compound semiconductor layer, and a part of the residual substrate part is notched bottom of the formed cutout portion is intended to be a light output surface or the reflection surface to the emission beam from the light emitting layer portion.

そして、本発明の発光素子の製造方法は、上記発光素子の製造方法であって、
ＧａＡｓ単結晶からなる基板本体部の主表面に、ＧａＡｓと異なる組成のＩＩＩ−Ｖ族化合物半導体単結晶からなる分離用化合物半導体層をエピタキシャル成長し、該分離用化合物半導体層上にＧａＡｓ単結晶からなる副基板部をエピタキシャル成長することにより複合成長用基板を作成する複合成長用基板作成工程と、
副基板部の主表面上に、発光層部を有した主化合物半導体層をエピタキシャル成長する発光層部成長工程と、
分離用化合物半導体層を化学エッチングにて除去することにより複合成長用基板から副基板部を分離して主化合物半導体層の主裏面上への残留基板部となす基板本体部除去工程と、
残留基板部の一部を切り欠いて切欠き部を形成する切欠き部形成工程と、
を有することを特徴とする。
なお、本明細書において基板ないし化合物半導体層の厚さ方向における両主面のうち、「主表面」とは結晶成長側の主面を、「主裏面」とはその反対側の主面を意味するものとして統一的に記載する。 And the manufacturing method of the light emitting element of this invention is a manufacturing method of the said light emitting element,
A separation compound semiconductor layer made of a III-V compound semiconductor single crystal having a composition different from that of GaAs is epitaxially grown on the main surface of the substrate main body portion made of GaAs single crystal, and the separation compound semiconductor layer is made of GaAs single crystal. A composite growth substrate creating step for creating a composite growth substrate by epitaxially growing the sub-substrate portion;
A light emitting layer portion growth step of epitaxially growing a main compound semiconductor layer having a light emitting layer portion on the main surface of the sub-substrate portion;
Removing the separation compound semiconductor layer by chemical etching to separate the sub-substrate portion from the compound growth substrate to form a residual substrate portion on the main back surface of the main compound semiconductor layer; and
A notch portion forming step of notching a part of the remaining substrate portion to form a notch portion;
It is characterized by having.
In this specification, of both main surfaces in the thickness direction of the substrate or compound semiconductor layer, “main surface” means the main surface on the crystal growth side, and “main back surface” means the main surface on the opposite side. List them consistently.

上記本発明においては、基板本体部、分離用化合物半導体層及び副基板部からなる複合成長用基板の、発光層部の結晶成長に使用する主面、すなわち主表面側をなす副基板部を複合成長用基板から分離し、発光層部を含む主化合物半導体層の主裏面側に残して残留基板部とする。さらに、残留基板部の一部を切り欠いて切欠き部を形成し、該切欠き部の底面を、発光層部からの発光光束に対する光取出面又は反射面として利用することにより、素子の光取出し効率を高めることができる。他方、ＧａＡｓ単結晶からなる残留基板部は素子構成要素として有効活用することができる。具体的には、次のような利用形態がある。
・発光層部の支持体とする。
・主化合物半導体層の主表面か主裏面のいずれかに、これを部分的に覆う光取出面側電極を形成する場合、その光取出面側電極直下領域への分配電流を迂回させるための電流阻止層とする。
・ＧａＡｓは電気陰性度が高いので、該ＧａＡｓ単結晶からなる残留基板部をオーミック接触形成用の接合合金化層の形成領域として利用し、素子の順方向電圧低減に寄与させる。なお、「主化合物半導体層」は、発光層部を含む化合物半導体の積層体を、切欠き部底面を含む平面にて厚さ方向に二分したとき、発光層部を含んでいる部分のことをいう。 In the present invention, the main surface used for crystal growth of the light emitting layer portion, that is, the sub substrate portion forming the main surface side of the composite growth substrate comprising the substrate main body portion, the separating compound semiconductor layer, and the sub substrate portion is combined. The substrate is separated from the growth substrate and left on the main back surface side of the main compound semiconductor layer including the light emitting layer portion to form a residual substrate portion. Further, a part of the residual substrate part is cut out to form a notch part, and the bottom surface of the notch part is used as a light extraction surface or a reflection surface for the luminous flux from the light emitting layer part. The extraction efficiency can be increased. On the other hand, the residual substrate portion made of GaAs single crystal can be effectively used as an element component. Specifically, there are the following usage modes.
-Use as a support for the light emitting layer.
・ When a light extraction surface side electrode that partially covers this is formed on either the main surface or the main back surface of the main compound semiconductor layer, the current for bypassing the distribution current to the region immediately below the light extraction surface side electrode A blocking layer.
Since GaAs has a high electronegativity, the residual substrate portion made of the GaAs single crystal is used as a region for forming a bonded alloy layer for forming an ohmic contact, and contributes to a reduction in the forward voltage of the device. The “main compound semiconductor layer” refers to a portion including the light emitting layer portion when the stack of compound semiconductors including the light emitting layer portion is divided in the thickness direction by a plane including the bottom surface of the cutout portion. Say.

また、素子構成要素として成長用基板を利用する際に、結晶成長工程でのハンドリング等を考慮した基板の適性厚さは、素子構成要素として利用する際の適性厚さよりもはるかに大きいので、適当な厚さの残留基板部を形成するには、発光層部を成長後に成長用基板の厚みを大幅に減ずる必要がある。本発明では、基板本体部と異なる組成のＩＩＩ−Ｖ族化合物半導体単結晶からなる分離用化合物半導体層をエピタキシャル成長し、該分離用化合物半導体層上にＧａＡｓ単結晶からなる副基板部をエピタキシャル成長することにより、成長用基板を複合成長用基板として形成する。そして、副基板部の主表面に例えばＡｌＧａＩｎＰからなる発光層部を有した主化合物半導体層をエピタキシャル成長し、分離用化合物半導体層をなす化合物半導体とＧａＡｓとの化学エッチングに対するエッチング速度の差を利用して、分離用化合物半導体層を化学エッチングにて除去することにより複合成長用基板部から副基板部を分離する。これにより、成長用基板の減厚工程を非常に簡単に行なうことができ、また、副基板部を分離用化合物半導体層上へのエピタキシャル層として構成することで、該副基板部に基づく残留基板部の厚さ精度を向上させることができる。さらには、分離用化合物半導体層と接する副基板部の主裏面が、機械的な加工が関与しない化学エッチング面となるので、該副基板部に基づく残留基板部の結晶品質も高めることができる。 In addition, when using a growth substrate as an element component, the appropriate thickness of the substrate considering handling in the crystal growth process is much larger than the appropriate thickness when used as an element component. In order to form a residual substrate portion having a sufficient thickness, it is necessary to greatly reduce the thickness of the growth substrate after the light emitting layer portion is grown. In the present invention, a separation compound semiconductor layer made of a group III-V compound semiconductor single crystal having a composition different from that of the substrate body is epitaxially grown, and a sub-substrate portion made of GaAs single crystal is epitaxially grown on the separation compound semiconductor layer. Thus, the growth substrate is formed as a composite growth substrate. Then, the main compound semiconductor layer having a light emitting layer portion made of, for example, AlGaInP is epitaxially grown on the main surface of the sub-substrate portion, and the difference in etching rate for chemical etching between the compound semiconductor forming the compound semiconductor layer for separation and GaAs is utilized. The sub-substrate portion is separated from the compound growth substrate portion by removing the separating compound semiconductor layer by chemical etching. Thereby, the thickness reduction process of the growth substrate can be performed very easily, and the sub-substrate portion is formed as an epitaxial layer on the compound semiconductor layer for separation, so that the residual substrate based on the sub-substrate portion is formed. The thickness accuracy of the part can be improved. Furthermore, since the main back surface of the sub-substrate portion in contact with the separating compound semiconductor layer is a chemically etched surface that does not involve mechanical processing, the crystal quality of the residual substrate portion based on the sub-substrate portion can be improved.

複合成長用基板から副基板部を分離する具体的な方法には、次の２種がある。
（１）分離用化合物半導体層をエッチストップ層とし、ＧａＡｓに対して選択エッチング性を有する第一エッチング液を用いて基板本体部をエッチング除去し、次いでエッチストップ層に対して選択エッチング性を有する第二エッチング液を用いてエッチストップ層をエッチング除去する。なお、基板本体部は、主裏面側から平面研削等の機械研削により予め減厚しておき、その後エッチングするようにしてもよい。エッチストップ層としては例えばＡｌＩｎＰ層を利用できる。
（２）分離用化合物半導体層を剥離層として形成し、その剥離層を選択エッチングすることにより、複合成長用基板から副基板部を分離する。この方法は、副基板部の分離（剥離）時に基板本体部が消失せず、次の発光素子の製造時に該基板本体部を再利用できる利点がある。 There are the following two types of specific methods for separating the sub-substrate portion from the composite growth substrate.
(1) The isolation compound semiconductor layer is used as an etch stop layer, and the substrate main body is etched away using a first etchant having selective etching properties with respect to GaAs, and then has selective etching properties with respect to the etch stop layer. The etch stop layer is etched away using a second etchant. The substrate main body may be previously reduced in thickness by mechanical grinding such as surface grinding from the main back surface side and then etched. For example, an AlInP layer can be used as the etch stop layer.
(2) The separation compound semiconductor layer is formed as a release layer, and the release layer is selectively etched to separate the sub-substrate portion from the composite growth substrate. This method has an advantage that the substrate main body portion is not lost when the sub-substrate portion is separated (peeled), and the substrate main body portion can be reused when the next light emitting element is manufactured.

基板本体部上に副基板部をエピタキシャル成長する工程としては、２０μｍ以下の比較的薄い副基板部を形成したい場合は周知のＭＯＶＰＥ（Metal-Organic Vapor Phase Epitaxy）法を利用できる。他方、２０μｍを超える厚い副基板部を形成したい場合は、ハイドライド気相成長法（Hydride Vapor Phase Epitaxial Growth Method：ＨＶＰＥ）を用いると能率的である。ＨＶＰＥ法は、蒸気圧の低いＧａ（ガリウム）を塩化水素との反応により気化しやすいＧａＣｌに転換し、該ＧａＣｌを媒介とする形でＶ族元素源ガスとＧａとを反応させることにより、ＩＩＩ−Ｖ族化合物半導体層の気相成長を行なう方法である。前述のＭＯＶＰＥ法による層成長速度は例えば約４μｍ／時程度と小さく、厚く副基板部を形成したい場合は、能率の点で明らかに不利である。これに対して、ＨＶＰＥ法の層成長速度は例えば約９μｍ／時とＭＯＶＰＥ法の２倍以上にも及び、副基板部を非常に高能率にて形成できるほか、高価な有機金属を使用しないので、原材料費をＭＯＶＰＥ法よりもはるかに低く抑えることができる。また、ＭＯＶＰＥ法では得られる化合物半導体層にＨやＣの残留量が多く、望む導電率が得られない場合があるが、ＨＶＰＥ法により成長した層は、ＭＯＶＰＥ法と異なりＣやＨの残留が生じにくく、具体的にはＣやＨの残留濃度を１×１０１８／ｃｍ３以下に留めることが極めて容易となる。ＨＶＰＥ法（ハイドライド気相成長法）により形成された透明厚膜半導体層のＣ及びＨ濃度は、例えば７×１０１７／ｃｍ３以下に留めることが可能であり、検出限界以下（例えば１×１０１７／ｃｍ３程度あるいはそれ以下）とすることも比較的容易である。 As a step of epitaxially growing the sub-substrate portion on the substrate body, a well-known MOVPE (Metal-Organic Vapor Phase Epitaxy) method can be used when it is desired to form a relatively thin sub-substrate portion of 20 μm or less. On the other hand, when it is desired to form a thick sub-substrate portion exceeding 20 μm, it is efficient to use a hydride vapor phase growth method (HVPE). In the HVPE method, Ga (gallium) having a low vapor pressure is converted into GaCl which is easily vaporized by reaction with hydrogen chloride, and a group V element source gas and Ga are reacted in a form mediated by the GaCl. This is a method for performing vapor phase growth of a group V compound semiconductor layer. The layer growth rate by the above-mentioned MOVPE method is as small as about 4 μm / hour, for example, and it is clearly disadvantageous in terms of efficiency when it is desired to form a thick sub-substrate portion. On the other hand, the layer growth rate of the HVPE method is, for example, about 9 μm / hour, more than twice that of the MOVPE method, and the sub-substrate portion can be formed with very high efficiency, and no expensive organic metal is used. The raw material cost can be kept much lower than the MOVPE method. In addition, the compound semiconductor layer obtained by the MOVPE method has a large amount of residual H and C, and the desired conductivity may not be obtained. However, unlike the MOVPE method, the layer grown by the HVPE method has residual C and H. In particular, it is extremely easy to keep the residual concentration of C and H at 1 × 10 18 / cm 3 or less. The C and H concentration of the transparent thick film semiconductor layer formed by the HVPE method (hydride vapor phase epitaxy) can be kept at, for example, 7 × 10 17 / cm 3 or less, and below the detection limit (for example, 1 × 10 10 17 / cm 3 or less) is also relatively easy.

副基板部は上記のごとく基板本体部上にエピタキシャル成長することにより形成されるものであるから、その主表面は、研磨等により形成された主表面と比較してダメージや結晶欠陥も少ない。従って、主化合物半導体層を副基板部の主表面に接してバッファ層を介することなくエピタキシャル成長しても、十分に高品質の発光層部を得ることができる。当然、バッファ層を形成しないので工程の簡略化を図ることができる。 Since the sub-substrate portion is formed by epitaxial growth on the substrate body portion as described above, the main surface thereof is less damaged and crystal defects than the main surface formed by polishing or the like. Therefore, even when the main compound semiconductor layer is in contact with the main surface of the sub-substrate portion and epitaxially grown without passing through the buffer layer, a sufficiently high-quality light emitting layer portion can be obtained. Of course, since the buffer layer is not formed, the process can be simplified.

以下、本発明の適用対象となる発光素子の具体的な態様につき、個別に説明する。
（第一態様）
発光層部に発光駆動電圧を印加するために光取出側電極が、主化合物半導体層の主表面の一部を覆って形成され、該主表面の光取出側電極に覆われていない領域が主光取出面とされ、
主化合物半導体層の主裏面側に位置する残留基板部を一部切り欠く形で、該残留基板部の主裏面に開口する切欠き部としての開口部が形成されるとともに、該開口部の周縁に残留基板部が残され、
開口部に、発光層部からの発光光束を反射させる反射部が設けられたことを特徴とする。本発明において素子の「光取出面」とは、発光光束が外部に取出可能となっている素子表面のことであり、「主光取出面」とは、第一態様、第二態様及び第四態様においては主化合物半導体層の主表面に形成される光取出面のことを、また第三態様においては主化合物半導体層の主裏面に形成される光取出面のことを、それぞれ意味する。また、上記主光取出面以外にも、主化合物半導体層に含まれる後述の透明厚膜半導体層あるいは補助電流拡散層の側面や、主化合物半導体層に形成される切欠き部の底面などが光取出面を構成可能である。 Hereinafter, specific modes of the light-emitting element to which the present invention is applied will be individually described.
(First aspect)
A light extraction side electrode is formed so as to cover a part of the main surface of the main compound semiconductor layer in order to apply a light emission driving voltage to the light emitting layer portion, and a region not covered by the light extraction side electrode of the main surface is a main region. The light extraction surface,
A part of the residual substrate portion located on the main back surface side of the main compound semiconductor layer is cut out to form an opening as a notch opening in the main back surface of the residual substrate portion, and the periphery of the opening portion The residual substrate part is left on the
The opening is provided with a reflection part for reflecting the luminous flux from the light emitting layer. In the present invention, the “light extraction surface” of the element refers to the surface of the element from which the luminous flux can be extracted to the outside, and the “main light extraction surface” refers to the first aspect, the second aspect, and the fourth aspect. In the embodiment, it means the light extraction surface formed on the main surface of the main compound semiconductor layer, and in the third embodiment, it means the light extraction surface formed on the main back surface of the main compound semiconductor layer. In addition to the main light extraction surface, the side surface of a transparent thick film semiconductor layer or auxiliary current diffusion layer, which will be described later, included in the main compound semiconductor layer, the bottom surface of a notch formed in the main compound semiconductor layer, etc. The extraction surface can be configured.

第一態様の発光素子においては、残留基板部の一部を切り欠く形で該残留基板部の主裏面に開口部を形成し、その開口部に、発光層部からの発光光束を反射させる反射部を設ける。成長用の副基板部の一部が残留基板部として発光層部への剛性付与の機能を果たせば、発光層部の主裏面側にはシリコン基板などの導電性基板を補強目的で新たに貼り合わせる必要がなくなる。そして、反射部自体は形成された開口部に基板貼り合わせを前提とせずに配置すればよく、当然、貼り合わせ熱処理も不要なので、反射部が冶金的反応等により反射率を落とす心配もない。かくして、第一態様の採用により、反射部をなす金属層を介してシリコン基板などの素子基板を発光層部に貼り合わせる工程が本質的に不要であり、しかも製造時のハンドリングに耐える十分な剛性も容易に確保できる発光素子が実現する。 In the light emitting device of the first aspect, an opening is formed in the main back surface of the residual substrate portion so as to cut out a portion of the residual substrate portion, and the reflection for reflecting the luminous flux from the light emitting layer portion is formed in the opening. Provide a part. If a part of the growth sub-board part functions as a residual substrate part and imparts rigidity to the light-emitting layer part, a conductive substrate such as a silicon substrate is newly attached to the main back side of the light-emitting layer part for the purpose of reinforcement. There is no need to match. The reflecting portion itself may be disposed in the formed opening without assuming that the substrates are bonded together. Naturally, the bonding heat treatment is not necessary, so that there is no concern that the reflecting portion will reduce the reflectance due to metallurgical reaction or the like. Thus, the adoption of the first aspect essentially eliminates the need for a step of bonding an element substrate such as a silicon substrate to the light emitting layer portion through the metal layer forming the reflective portion, and is sufficiently rigid to withstand handling during manufacturing. Thus, a light emitting element that can be easily secured is realized.

切欠き部を形成する際には、厚さが十分（例えば２０ｎｍ以下）に小さければ、残留基板部の一部が切欠き部の底位置に残留していても差し支えない。しかし、反射率を可及的に高める観点においては、ＧａＡｓ残留基板部に由来した光吸収性の化合物半導体がなるべく切欠き部の底に残留していないこと、つまり、切欠き部が残留基板部を厚さ方向に貫通して形成され、（残留基板部よりも光吸収性の小さい）主化合物半導体層の主裏面を切欠き部に露出させることが望ましい。 When forming the cutout portion, if the thickness is sufficiently small (for example, 20 nm or less), a part of the remaining substrate portion may remain at the bottom position of the cutout portion. However, from the viewpoint of increasing the reflectivity as much as possible, the light-absorbing compound semiconductor derived from the GaAs residual substrate portion does not remain as much as possible at the bottom of the notch portion, that is, the notch portion is the residual substrate portion. It is desirable to expose the main back surface of the main compound semiconductor layer (having a smaller light absorption than the residual substrate portion) in the notch portion.

第一態様の発光素子は、光取出し効率を高めるために、次のように構成することが有効である。すなわち、開口部を、主光取出面の直下領域と重なる形で形成し、該開口部内にて反射部を、主光取出面の直下領域と重なる形で設ける。このようにすると、主光取出面の直下位置に反射部を臨ませることができ、反射光束をより効率的に取り出すことができるので、発光素子全体のさらなる発光強度増加に寄与する。 In order to increase the light extraction efficiency, it is effective to configure the light emitting element of the first aspect as follows. That is, the opening is formed so as to overlap with the region directly under the main light extraction surface, and the reflection portion is provided within the opening so as to overlap with the region directly under the main light extraction surface. If it does in this way, a reflection part can be made to face directly under a main light extraction surface, and since a reflected light beam can be taken out more efficiently, it contributes to the further increase in luminescence intensity of the whole light emitting element.

一方、開口部を光取出側電極の直下領域と重なる形で形成し、該開口部内にて反射部を、該光取出側電極の直下領域と重なる形で設けることもできる。光取出側電極の直下領域に設けた反射部は、直上方向への反射光は光取出側電極に遮られるものの、電極外形線を見込む角度よりも大きな角度で斜めに反射される光は、光取出側電極外側の光取出領域から外部に取り出すことができ、反射光束のより効率的な取出しに寄与する。なお、主光取出面の直下領域に加え、さらに光取出側電極の直下領域にも反射部を設けることで反射光束の取出し効率が一層高められることは、いうまでもない。   On the other hand, the opening may be formed so as to overlap with the region directly under the light extraction side electrode, and the reflection portion may be provided within the opening so as to overlap with the region directly under the light extraction side electrode. The reflection part provided in the region directly under the light extraction side electrode reflects light obliquely at an angle larger than the angle at which the electrode outline is viewed, although the reflected light in the directly upward direction is blocked by the light extraction side electrode. The light can be extracted from the light extraction region outside the extraction side electrode, which contributes to more efficient extraction of the reflected light beam. Needless to say, in addition to the region directly under the main light extraction surface, a reflection portion is also provided in the region directly under the light extraction side electrode, whereby the extraction efficiency of the reflected light flux can be further improved.

素子の発光強度を高めるには、主光取出面に臨む発光層部領域に電流を一様に供給することが重要であり、特に、光取出側電極から離れた領域にも十分な電流を供給するには、発光層部と光取出側電極との間に電流拡散層を設けておくことが有効である。電流拡散層は、発光層部よりもドーパント濃度を高めた化合物半導体層として形成することができるほか、ＩＴＯ(Indium Tin Oxide）などの導電性酸化物層として形成することもできる。   In order to increase the light emission intensity of the device, it is important to supply current uniformly to the light emitting layer area facing the main light extraction surface, and in particular, supply sufficient current to the area away from the light extraction side electrode. For this purpose, it is effective to provide a current diffusion layer between the light emitting layer portion and the light extraction side electrode. The current spreading layer can be formed as a compound semiconductor layer having a dopant concentration higher than that of the light emitting layer, and can also be formed as a conductive oxide layer such as ITO (Indium Tin Oxide).

主光取出面は、該電流拡散層の主表面周縁に沿って光取出側電極を取り囲む形態で形成されることが好ましい。このようにすると、光取出側電極の周囲領域に電流を一様に供給することができ、光取出し効率向上に寄与する。この場合、発光層部への通電経路を構成する残留基板部を、該発光層部を含む主化合物半導体層の主裏面の周縁に沿って枠状に形成し、当該枠状の残留基板部の内側に前記の開口部を形成することができる。枠状の残留基板部を設けることで、光取出側電極を取り囲む主光取出面に電流を集中させることができ、発光層部を光取出しに有利な領域で優先的に発光させることができるので、光取出し効率を一層向上させることができる。 The main light extraction surface is preferably formed in a form surrounding the light extraction side electrode along the periphery of the main surface of the current diffusion layer. If it does in this way, an electric current can be uniformly supplied to the surrounding area | region of a light extraction side electrode, and it contributes to light extraction efficiency improvement. In this case, the residual substrate part constituting the energization path to the light emitting layer part is formed in a frame shape along the peripheral edge of the main back surface of the main compound semiconductor layer including the light emitting layer part, and the frame-like residual substrate part The opening can be formed inside. By providing the frame-like residual substrate portion, current can be concentrated on the main light extraction surface surrounding the light extraction side electrode, and the light emitting layer portion can be preferentially emitted in an area advantageous for light extraction. The light extraction efficiency can be further improved.

上記の構成においては、光取出側電極の主化合物半導体層の主裏面への投影外形線を、枠状の残留基板部の内側に位置させることができる。そして、開口部において、該枠状の残留基板部の内縁と光取出側電極の投影外形線との間に位置する領域を反射部にて覆うことができる。この構造によると、光取出側電極を取り囲む光取出領域と枠状の残留基板部との間に形成される一定幅の領域において、反射部による反射光束を効果的に取り出すことができ、光取出し効率の更なる向上に寄与する。 In the above configuration, the projected outline on the main back surface of the main compound semiconductor layer of the light extraction side electrode can be positioned inside the frame-like residual substrate portion. Then, in the opening, the region located between the inner edge of the frame-like residual substrate portion and the projected outline of the light extraction side electrode can be covered with the reflection portion. According to this structure, in a constant width region formed between the light extraction region surrounding the light extraction side electrode and the frame-like residual substrate portion, the reflected light beam by the reflection portion can be effectively extracted, and the light extraction Contributes to further improvement in efficiency.

また、光取出側電極の直下領域においては、主化合物半導体層と反射部との接触抵抗を、主化合物半導体層と残留基板部との接触抵抗よりも高くすることができる。光取出側電極の直下領域では、発光層部をいくら光らせても発光光束の多くが光取出側電極に遮られ、外部に効率よく取り出すことができない。従って、光取出側電極の直下領域で通電電流を大きくすることは得策でない。そこで上記のように、開口部において、光取出側電極の直下領域に反射部を配置し、かつ、該反射部と主化合物半導体層との接触抵抗を、残留基板部と主化合物半導体層との接触抵抗よりも高くすることで、光取出側電極の直下領域に分配される通電電流を少なくすることができ、その分、主光取出面の直下に位置する残留基板部側の発光層部領域に電流を優先的に流すことができるので、光取出し効率を増加させることができる。   Further, in the region immediately below the light extraction side electrode, the contact resistance between the main compound semiconductor layer and the reflecting portion can be made higher than the contact resistance between the main compound semiconductor layer and the residual substrate portion. In the region immediately below the light extraction side electrode, no matter how much the light emitting layer portion is illuminated, most of the emitted light flux is blocked by the light extraction side electrode and cannot be efficiently extracted outside. Therefore, it is not a good idea to increase the energizing current in the region immediately below the light extraction side electrode. Therefore, as described above, in the opening, the reflective portion is disposed in the region directly below the light extraction side electrode, and the contact resistance between the reflective portion and the main compound semiconductor layer is determined between the residual substrate portion and the main compound semiconductor layer. By making it higher than the contact resistance, the energization current distributed to the region directly under the light extraction side electrode can be reduced, and the light emitting layer portion region on the residual substrate portion side located immediately below the main light extraction surface accordingly. Since the current can be preferentially passed through the light, the light extraction efficiency can be increased.

また、反射部は金属反射部とすることができる。この場合、光取出側電極の直下領域において該金属反射部を、開口部の底面をなす主化合物半導体部層に対し、接合合金化層を介することなく、直接接して配置することができる。光取出側電極の直下領域から接合合金化層を排除することで、主化合物半導体層と反射部との接触抵抗を効果的に高めることができ、発光光束が遮光されやすい光取出側電極直下領域での発光を抑制して光取出し効率の更なる向上に寄与する。なお、開口部が、主光取出面の直下領域と重なる形で形成される場合は、金属反射部の全体に対して接合合金化層を排除する構成としてもよいが、主光取出面の直下領域には接合合金化層を分散形成するようにしてもよい。この場合、金属反射部は、開口部の底面をなす主化合物半導体部層に対し、主光取出面の直下領域においては接合合金化層を介して接することになり、主光取出面の直下領域において発光層部を、金属反射部を介して通電発光させることができる。これにより、光取出し効率がより向上する。   Further, the reflection part can be a metal reflection part. In this case, the metal reflecting portion can be arranged in direct contact with the main compound semiconductor portion layer forming the bottom surface of the opening portion without using the bonding alloying layer in the region immediately below the light extraction side electrode. By eliminating the bonding alloying layer from the region directly under the light extraction side electrode, the contact resistance between the main compound semiconductor layer and the reflecting portion can be effectively increased, and the region directly under the light extraction side electrode where the emitted light flux is easily shielded This contributes to further improvement of the light extraction efficiency by suppressing the light emission. When the opening is formed so as to overlap with the region directly below the main light extraction surface, the structure may be such that the bonded alloying layer is excluded from the entire metal reflection portion, but directly below the main light extraction surface. A bonded alloying layer may be dispersedly formed in the region. In this case, the metal reflecting portion is in contact with the main compound semiconductor portion layer forming the bottom surface of the opening via the bonding alloying layer in the region directly below the main light extraction surface, and the region immediately below the main light extraction surface. The light emitting layer portion can be energized and light-emitted through the metal reflecting portion. Thereby, the light extraction efficiency is further improved.

以上の構成において反射部は、開口部内に充填された金属ペースト層とすることができる。この方法によると、Ａｇペースト等の金属ペーストを塗布することにより開口部内に反射部を簡単に形成することができる。さらに、開口部の内側空間を、伝熱性の高い金属ペーストで充填することにより、発光層部の放熱を促進でき、通電による発光層部の温度上昇が抑制されるので、素子の長寿命化を図ることができる。この場合、残留基板部の主裏面を、開口部内を充填する金属ペースト層の主裏面とともに放熱用金属部材により覆うことができる。残留基板部にも放熱用金属部材を設けることにより、発光層部の放熱をさらに促進することができる。また、金属ペースト層を結合剤に兼用させることで、放熱用金属部材の発光層部（主化合物半導体層）への結合を、反射部を兼ねた金属ペースト層による貼り合わせにより簡単に行なうことができる。放熱用金属部材は、熱伝導率がなるべく高い金属で構成することが望ましく、具体的にはＡｌ又はＣｕのいずれかを主成分（５０質量％以上；１００質量％含む）とする金属で構成するとよい。具体的には、Ａｌ金属板ないしＣｕ金属板を用いることで、高性能の放熱用金属部材を安価に構成することができる。また、Ｃｕ−Ｗ合金は熱容量も高く、放熱性に特に優れた効果を発揮する。 In the above configuration, the reflection portion can be a metal paste layer filled in the opening. According to this method, the reflective part can be easily formed in the opening by applying a metal paste such as an Ag paste. Furthermore, by filling the inner space of the opening with a metal paste having high heat conductivity, heat dissipation of the light emitting layer can be promoted, and the temperature rise of the light emitting layer due to energization is suppressed, so the life of the element can be extended. Can be planned. In this case, the main back surface of the residual substrate portion can be covered with the heat radiating metal member together with the main back surface of the metal paste layer filling the opening. By providing a metal member for heat dissipation also on the remaining substrate portion, heat dissipation of the light emitting layer portion can be further promoted. Further, by using the metal paste layer also as a binder, the heat radiating metal member can be easily bonded to the light emitting layer portion (main compound semiconductor layer) by bonding with the metal paste layer also serving as the reflection portion. it can. The metal member for heat dissipation is preferably composed of a metal having as high a thermal conductivity as possible. Specifically, when the metal member is composed of a metal containing either Al or Cu as a main component (including 50 mass% or more; 100 mass%). Good. Specifically, by using an Al metal plate or a Cu metal plate, a high-performance heat radiating metal member can be configured at low cost. In addition, the Cu—W alloy has a high heat capacity and exhibits particularly excellent heat dissipation.

また、金属ペースト層の外周縁部に一体化される形で、残留基板部の主裏面を覆う導通経路ペースト層を形成し、残留基板部の主裏面には、導通経路ペースト層との接触抵抗を減ずる接合合金化層を形成することができる。この構成によると、開口部が形成された主化合物半導体層の主裏面側に金属ペースト層を、残留基板部の形成領域とともに一括して塗付すればよく、反射部を兼ねた金属ペースト層の形成をより簡便に行なうことができる（導通経路ペースト層は開口部を充填する金属ペーストと同一の金属ペーストで形成される）。しかも、残留基板部の主裏面には接合合金化層が形成され、該接合合金化層を覆うように金属ペースト層の導通経路ペースト層が形成されるので、残留基板部と放熱用金属部材との間で、接合合金化層と導通経路ペースト層とを介して容易に通電でき、素子の直列抵抗の低減にも寄与する。 In addition, a conductive path paste layer that covers the main back surface of the residual substrate portion is formed so as to be integrated with the outer peripheral edge of the metal paste layer, and contact resistance with the conductive path paste layer is formed on the main back surface of the residual substrate portion. It is possible to form a bonded alloyed layer that reduces According to this configuration, the metal paste layer may be applied to the main back surface side of the main compound semiconductor layer in which the opening is formed, together with the formation region of the residual substrate portion, and the metal paste layer that also serves as the reflection portion may be applied. It can be formed more easily (the conductive path paste layer is formed of the same metal paste as the metal paste filling the opening). In addition, a bonding alloying layer is formed on the main back surface of the residual substrate portion, and a conductive path paste layer of the metal paste layer is formed so as to cover the bonding alloying layer. In between, it can be easily energized through the bonding alloying layer and the conduction path paste layer, which contributes to the reduction of the series resistance of the element.

他方、反射部は、開口部の底面をなす主化合物半導体部層上に成膜された反射金属層とすることができる。この構成は、蒸着やスパッタなどの成膜工程が必要になるが、反射金属層の平滑性が高められるので、より反射率の高い反射部を得ることができる。   On the other hand, the reflective portion can be a reflective metal layer formed on the main compound semiconductor portion layer forming the bottom surface of the opening. This configuration requires a film forming process such as vapor deposition and sputtering, but the smoothness of the reflective metal layer is improved, so that a reflective part with higher reflectivity can be obtained.

また、主化合物半導体層と残留基板部との間に、屈折率の相違する半導体膜を複数積層することにより、ブラッグ反射を利用して光を反射させるＤＢＲ（Distributed Bragg Reflector）層を設けることもできる。ＤＢＲ層は残留基板部上にエピタキシャル成長可能であり、主光取出面直下に位置する発光層部のうち、光吸収性を有する残留基板部直上に位置する領域であっても、反射光束を効果的に発生させることができ、ひいては光取出し効率をさらに高めることが可能となる。   Also, a DBR (Distributed Bragg Reflector) layer that reflects light using Bragg reflection may be provided by laminating a plurality of semiconductor films having different refractive indexes between the main compound semiconductor layer and the residual substrate portion. it can. The DBR layer can be epitaxially grown on the residual substrate portion, and the reflected light flux is effectively applied even in the region located immediately above the residual substrate portion having light absorption among the light emitting layer portion located immediately below the main light extraction surface. Therefore, the light extraction efficiency can be further increased.

（第二態様）
発光層部に発光駆動電圧を印加するために光取出側電極が、主化合物半導体層の主表面の一部を覆って形成され、該主表面の光取出側電極に覆われていない領域が主光取出面とされ、
主化合物半導体層の主裏面側に位置する残留基板部のうち、主光取出面の直下部分の少なくとも一部に切欠き部が形成され、かつ、光取出側電極の直下部分の少なくとも一部が残留基板部に含まれることを特徴とする。 (Second embodiment)
A light extraction side electrode is formed so as to cover a part of the main surface of the main compound semiconductor layer in order to apply a light emission driving voltage to the light emitting layer portion, and a region not covered by the light extraction side electrode of the main surface is a main region. The light extraction surface,
Of the remaining substrate portion located on the main back surface side of the main compound semiconductor layer, a notch is formed in at least part of the portion directly below the main light extraction surface, and at least part of the portion directly below the light extraction side electrode is It is included in the residual substrate portion.

第二態様の発光素子においては、残留基板部のうち、主光取出面の直下部分の少なくとも一部に切欠き部が形成され、かつ、光取出側電極の直下部分の少なくとも一部が残留基板部に含まれるように切り欠くようにした。光吸収部として作用するＧａＡｓ残留基板部が、主化合物半導体層の主裏面のうち主光取出面の直下領域となる部分で切り欠かれることにより、該部分へ向かう発光光束も外部へ取り出すことが可能となり、光取出し効率を高めることができる。他方、光取出側電極の直下領域には残留基板部の一部が残される。残留基板部は光吸収の作用を有するが、光取出側電極の直下領域にて仮に反射光を生じても光取出側電極に結局は遮られるので、この部分に残留基板部が残されることによる実害は少ない。そこで、残留基板部を光取出側電極の直下領域に残すことで、該残留基板部による光吸収の影響をそれほど顕著化することなく、発光層部への剛性付与の機能を担わせることができる。その結果、主化合物半導体層の主裏面側に、シリコン基板などの導電性基板を補強目的で新たに貼り合わせる必要がなくなる。 In the light emitting device of the second aspect, a notch portion is formed in at least a part of the residual substrate portion immediately below the main light extraction surface, and at least a part of the direct extraction portion of the light extraction side electrode is the residual substrate. Cut out to be included in the part. The GaAs residual substrate portion acting as a light absorbing portion is cut out at a portion of the main back surface of the main compound semiconductor layer that is immediately below the main light extraction surface, so that the emitted light flux directed to the portion can be extracted to the outside. This makes it possible to increase the light extraction efficiency. On the other hand, a part of the remaining substrate portion is left in the region directly below the light extraction side electrode. Although the residual substrate portion has a light absorption function, even if reflected light is generated in the region immediately below the light extraction side electrode, it is eventually blocked by the light extraction side electrode, so that the residual substrate portion remains in this portion. There is little real harm. Therefore, by leaving the residual substrate portion in the region immediately below the light extraction side electrode, it is possible to have a function of imparting rigidity to the light emitting layer portion without making the influence of light absorption by the residual substrate portion so significant. . As a result, it is not necessary to newly attach a conductive substrate such as a silicon substrate to the main back surface side of the main compound semiconductor layer for the purpose of reinforcement.

残留基板部と発光層部との間には、化合物半導体よりなる補助電流拡散層を設けておくことができる。これにより、切欠き部底面部への電流拡散効果が高められ、発光層部の該切欠き部に対応した領域への分配電流が増加するので、切欠き部底面から取り出される（ないし切欠き部底面にて反射される）発光光束をより増加することができる。なお、発光層部が、後述のＡｌＧａＩｎＰ等により、残留基板部に近い側から第一導電型クラッド層、活性層及び第二導電型クラッド層がこの順序で積層されたダブルへテロ構造を有するものとして構成される場合、該補助電流拡散層は、第一導電型クラッド層よりも有効キャリア濃度を高めておくことで、電流拡散効果をより顕著なものとすることができる。また、補助電流拡散層を設ける代わりに、第一導電型クラッド層を第二導電型クラッド層よりも厚く形成することもできる。該構成では、第一導電型クラッド層の主裏面側の部分（切欠き部底に近い側の表層部）が電流拡散層の役割を果たしていると見ることもできる。そして、該部分の有効キャリア濃度を残余の部分よりも高めておくことで、電流拡散効果をより顕著なものとすることができる。 An auxiliary current diffusion layer made of a compound semiconductor can be provided between the residual substrate portion and the light emitting layer portion. As a result, the current diffusion effect to the bottom surface of the notch is enhanced, and the distribution current to the region corresponding to the notch of the light emitting layer increases, so that it is taken out from the bottom of the notch (or the notch). The luminous flux (reflected at the bottom surface) can be further increased. In addition, the light emitting layer portion has a double hetero structure in which the first conductivity type cladding layer, the active layer, and the second conductivity type cladding layer are laminated in this order from the side close to the residual substrate portion by AlGaInP or the like described later. In this case, the auxiliary current diffusion layer can make the current diffusion effect more remarkable by increasing the effective carrier concentration as compared with the first conductivity type cladding layer. Further, instead of providing the auxiliary current diffusion layer, the first conductivity type cladding layer can be formed thicker than the second conductivity type cladding layer. In this configuration, it can be considered that the main back surface side portion of the first conductivity type cladding layer (the surface layer portion near the notch bottom) plays the role of the current diffusion layer. Further, by increasing the effective carrier concentration of the portion higher than that of the remaining portion, the current spreading effect can be made more remarkable.

この場合、残留基板部は、光取出側電極の直下部分を取り囲む形で、その周縁部に沿って上記切欠き部を形成しておけば、該切欠き部を利用して取り出される発光光束を、より増加させることができる。   In this case, if the remaining substrate portion surrounds the portion immediately below the light extraction side electrode and the notch portion is formed along the peripheral edge portion thereof, the emitted light flux extracted using the notch portion is reduced. Can be increased more.

具体的には、発光層部からの発光光束を切欠き部から外部へ取り出し可能とすることができる。すなわち、残留基板部に形成された切欠き部の底面部は、発光層部の主裏面側に補助的な光取出面を形成するので、ここから発光光束を直接取り出すことで、素子全体の光取出し効率を高めることができる。 Specifically, the luminous flux from the light emitting layer part can be taken out from the notch part. That is, the bottom surface portion of the notch portion formed in the residual substrate portion forms an auxiliary light extraction surface on the main back surface side of the light emitting layer portion. Extraction efficiency can be increased.

この場合、残留基板部の主裏面を、反射部材を兼ねた金属ステージ上に接着するとともに、切欠き部から取り出された発光光束を該金属ステージの反射面にて反射させるように構成することができる。この構成によると、切欠き部の底面から取り出された発光光束を金属ステージの反射面にて反射させることで、発光層部の主表面側への発光光束を大幅に増加させることができ、発光素子の該側への指向性を高めることができる。 In this case, the main back surface of the residual substrate portion can be adhered to a metal stage that also serves as a reflecting member, and the emitted light beam extracted from the notch portion can be reflected by the reflecting surface of the metal stage. it can. According to this configuration, the emitted light beam extracted from the bottom surface of the notch is reflected by the reflecting surface of the metal stage, so that the emitted light beam to the main surface side of the light emitting layer portion can be greatly increased, and light emission The directivity of the element toward the side can be increased.

一方、第二態様の発光素子は、上記切欠き部に発光層部からの発光光束を反射させる金属反射部を設けることもできる。切欠き部に金属反射部を設けることで、該領域で本来残留基板部に吸収されるはずの発光光束を、金属反射部による反射光束の形で取り出すことができ、光取出し効率を高めることができる。該金属反射部自体は前述の切欠き部の底面に、基板貼り合わせを前提とせずに配置すればよく、当然、貼り合わせ熱処理も不要なので、金属反射部が冶金的反応等により反射率を落とす心配もない。かくして、発光層部が金属反射部で覆われた構造を有しつつも、金属反射部をなす金属層を介してシリコン基板などの素子基板を発光層部に貼り合わせる工程が本質的に不要な発光素子が実現する。 On the other hand, the light emitting element of the second aspect can be provided with a metal reflecting portion that reflects the luminous flux from the light emitting layer portion in the notch portion. By providing a metal reflection part in the notch part, it is possible to take out the emitted light beam that should be absorbed by the residual substrate part in the region in the form of a reflected light beam by the metal reflection part, thereby improving the light extraction efficiency. it can. The metal reflection part itself may be disposed on the bottom surface of the above-mentioned notch part without assuming that the substrates are bonded together. Naturally, since the heat treatment for bonding is not required, the metal reflection part reduces the reflectance due to metallurgical reaction or the like. Don't worry. Thus, while the light emitting layer portion is covered with the metal reflecting portion, a process of attaching an element substrate such as a silicon substrate to the light emitting layer portion via the metal layer forming the metal reflecting portion is essentially unnecessary. A light emitting element is realized.

なお、切欠き部を光取出側電極の直下領域に入り込む形で形成し、該切欠き部内にて金属反射部を、光取出側電極の直下領域に入り込む形で形成することもできる。光取出側電極の直下領域に入り込む金属反射部は、直上方向への反射光は光取出側電極に遮られるものの、光取出側電極外形線を見込む角度よりも大きな角度で斜めに反射される光は、光取出側電極外側の光取出領域から外部に取り出すことができ、反射光束のより効率的な取り出しに寄与する。一方、残留基板部による光吸収の不利が極端に顕在化しない範囲であれば、残留基板部を主光取出面の直下領域に入り込む形で形成しても差し支えない。   Alternatively, the cutout portion may be formed so as to enter the region directly under the light extraction side electrode, and the metal reflection portion may be formed within the cutout portion so as to enter the region directly under the light extraction side electrode. The metal reflector that enters the region directly below the light extraction side electrode reflects light obliquely at an angle larger than the angle at which the light extraction side electrode outline is viewed, although the light reflected in the upward direction is blocked by the light extraction side electrode Can be taken out from the light extraction area outside the light extraction side electrode, and contributes to more efficient extraction of the reflected light flux. On the other hand, as long as the disadvantage of light absorption by the residual substrate portion is not extremely obvious, the residual substrate portion may be formed so as to enter the region immediately below the main light extraction surface.

素子の発光強度を高めるには、主光取出面に臨む発光層部領域に電流を一様に供給することが重要であり、特に、光取出側電極から離れた領域にも十分な電流を供給するには、発光層部と光取出側電極との間に、第一態様と同様の電流拡散層を設けておくことが有効である。上記のような電流拡散層を設ける場合、主光取出面を該電流拡散層の主表面周縁に沿って光取出側電極を取り囲む形態で形成することができる。このようにすると、光取出側電極の周囲領域に電流を一様に供給することができ、光取出し効率向上に寄与する。また、比較的厚い電流拡散層（例えば厚さ２０μｍ以上２００μｍ以下）を形成しておくことで、該電流拡散層の周側面からの取出光束も高めることができ、光取出し効率のさらなる向上に寄与する。 In order to increase the light emission intensity of the element, it is important to supply current uniformly to the light emitting layer area facing the main light extraction surface, and in particular, supply sufficient current to the area away from the light extraction side electrode. For this purpose, it is effective to provide a current diffusion layer similar to that in the first embodiment between the light emitting layer portion and the light extraction side electrode. When the current diffusion layer as described above is provided, the main light extraction surface can be formed so as to surround the light extraction side electrode along the periphery of the main surface of the current diffusion layer. If it does in this way, an electric current can be uniformly supplied to the surrounding area | region of a light extraction side electrode, and it contributes to light extraction efficiency improvement. In addition, by forming a relatively thick current diffusion layer (for example, a thickness of 20 μm or more and 200 μm or less), it is possible to increase the extracted light flux from the peripheral side surface of the current diffusion layer, contributing to further improvement of the light extraction efficiency. To do.

また、切欠き部の底面に、金属反射部との接触抵抗を減ずるための接合合金化層を形成することができる。これにより、金属反射部を発光層部駆動用の裏面電極として機能させることができる。なお、接合合金化層は層形成用の金属材料薄膜を切欠き部底面に形成し、さらに合金化熱処理することにより形成できる。接合合金化層は切欠き部底面の全面に形成することもできるが、上記の合金化により、接合合金化層の反射率の低下が著しい場合は、切欠き部底面に接合合金化層を分散形成することが有効である。個々の接合合金化層の背景領域にて金属反射部が切欠き部の底面と接して配置されることで、該背景領域では良好な反射率を確保でき、接合合金化層を切欠き部の底面全面にベタ形成する場合よりも全体としての反射率を向上させることができる。   Moreover, the joining alloying layer for reducing contact resistance with a metal reflective part can be formed in the bottom face of a notch part. Thereby, a metal reflective part can be functioned as a back surface electrode for light emitting layer part drive. The bonded alloyed layer can be formed by forming a metal material thin film for forming a layer on the bottom surface of the notch and further heat-treating the alloy. The bonding alloyed layer can be formed on the entire bottom surface of the notch. However, if the above alloying causes a significant decrease in the reflectance of the bonded alloyed layer, the bonding alloyed layer is dispersed on the bottom surface of the notched portion. It is effective to form. In the background region of each bonding alloyed layer, the metal reflecting portion is disposed in contact with the bottom surface of the notch, so that a good reflectivity can be secured in the background region, and the bonding alloyed layer of the notched portion can be secured. The reflectance as a whole can be improved as compared with the case where a solid is formed on the entire bottom surface.

また、残留基板部の主裏面を、前記金属反射部を含む一体の金属部にて覆うことができる。このようにすると、発光素子の主裏面側（つまり素子の裏面側）を切欠き部の底面とともに金属部により一括して覆えばよく、工程の簡略化に寄与する。この場合、残留基板部の形成領域における素子厚さ方向の電気抵抗を、かつ切欠き部の形成領域における素子厚さ方向の電気抵抗よりも高く調整しておくことが望ましい。光取出側電極の直下領域では、発光層部をいくら光らせても発光光束の多くが光取出側電極に遮られ、外部に効率よく取り出すことができない。従って、光取出側電極の直下領域で通電電流を大きくすることは得策でない。そこで上記のように構成すれば、光取出側電極の直下領域に分配される通電電流を少なくすることができる。その結果、主光取出面の直下に位置する切欠き部側の発光層部領域に電流を優先的に流すことができるので、光取出し効率を増加させることができる。 Moreover, the main back surface of the residual substrate part can be covered with an integral metal part including the metal reflection part. If it does in this way, what is necessary is just to cover the main back surface side (namely, back surface side of an element) of a light emitting element collectively with a metal part with the bottom face of a notch part, and contributes to simplification of a process. In this case, it is desirable that the electrical resistance in the element thickness direction in the formation region of the residual substrate portion is adjusted to be higher than the electrical resistance in the element thickness direction in the formation region of the notch portion. In the region immediately below the light extraction side electrode, no matter how much the light emitting layer portion is illuminated, most of the emitted light flux is blocked by the light extraction side electrode and cannot be efficiently extracted outside. Therefore, it is not a good idea to increase the energizing current in the region immediately below the light extraction side electrode. Therefore, if configured as described above, the energization current distributed to the region immediately below the light extraction side electrode can be reduced. As a result, the current can be preferentially passed through the light emitting layer portion region on the notch portion side located immediately below the main light extraction surface, so that the light extraction efficiency can be increased.

上記のように素子の電気抵抗分布を調整するには、種々の方法が存在する。具体的には、残留基板部の主裏面を、金属部との接触抵抗を減ずるための接合合金化層を非形成のものとして構成することができる（構成１）。また、残留基板部を、発光層部にてｐ−ｎ接合を形成するｐ型層部とｎ型層部とのうち、該残留基板部に近い側のものと逆の導電型を有するものとして構成することもできる（構成２）。さらには、残留基板部を、発光層部にてｐ−ｎ接合を形成するｐ型層部とｎ型層部とのうち、該残留基板部に近い側のものと同一の導電型を有するものとし、かつ、発光層部と残留基板部との間に、残留基板部を被覆する形で、該残留基板部と逆の導電型を有する化合物半導体からなる反転層部を介挿することも可能である（構成３）。これらの構成により、発光光束が遮光されやすい光取出側電極直下領域での発光を抑制して光取出し効率のさらなる向上に寄与する。 There are various methods for adjusting the electrical resistance distribution of the element as described above. Specifically, the main back surface of the residual substrate portion can be configured as a non-formed bonding alloyed layer for reducing the contact resistance with the metal portion (Configuration 1). Further, the residual substrate portion has a conductivity type opposite to that of the p-type layer portion and the n-type layer portion that form a pn junction in the light emitting layer portion and closer to the residual substrate portion. It can also be configured (Configuration 2). Further, the remaining substrate portion has the same conductivity type as the one close to the remaining substrate portion among the p-type layer portion and the n-type layer portion that form a pn junction in the light emitting layer portion. In addition, an inversion layer portion made of a compound semiconductor having a conductivity type opposite to that of the residual substrate portion may be interposed between the light emitting layer portion and the residual substrate portion so as to cover the residual substrate portion. (Configuration 3). With these configurations, it is possible to suppress light emission in the region immediately below the light extraction side electrode where the emitted light flux is easily shielded, thereby contributing to further improvement in light extraction efficiency.

残留基板部の主裏面は、Ａｇペースト等の金属ペースト層を介して支持体に接着することができる。支持体は、例えば金属ステージや、該金属ステージとは別に設けられた後述の放熱用金属部材である。この場合、素子に形成された前述の切欠き部は、上記接着時において主化合物半導体層の周側面側に這い上がろうとする金属ペーストの吸収空間として利用できる。このようにすると、這い上がった金属ペーストにより主化合物半導体層に含まれる発光層部のｐ−ｎ接合が短絡するなどの不具合を効果的に防止することができる。この場合、残留基板部の厚さを４０μｍ以上に確保しておくと、上記効果を一層顕著なものとすることができる。また、素子底面に金属ペースト層を塗布して金属ステージなどの支持体に接着する際に、素子底面と支持体表面との間に介在する金属ペースト層の厚さに応じて、光取出面側電極が形成される素子上面の高さ位置がばらつくことがあり、例えば光取出面側電極へのワイヤボンディングを自動で行う際に、一様なボンディング状態を得る上で不都合を生ずる場合もありうる。しかし、上記の構成によると、残留基板部の主裏面を支持体表面に密着させ、切欠き部内に充填された金属ペースト層により接着を行なうようにすれば、残留基板部の厚さ制御により金属ペースト層の厚さを一様に揃えることができ、接着後の光取出面側電極の高さ方向位置のバラツキを軽減できる（該効果は、第一態様でも同様に発揮される）。 The main back surface of the remaining substrate portion can be bonded to the support through a metal paste layer such as an Ag paste. The support is, for example, a metal stage or a metal member for heat dissipation described later provided separately from the metal stage. In this case, the aforementioned notch formed in the element can be used as an absorption space for the metal paste that tends to crawl up to the peripheral side surface of the main compound semiconductor layer during the bonding. By doing so, it is possible to effectively prevent such a problem that the pn junction of the light emitting layer portion included in the main compound semiconductor layer is short-circuited by the scooped metal paste. In this case, if the thickness of the residual substrate portion is secured to 40 μm or more, the above effect can be made more remarkable. In addition, when a metal paste layer is applied to the bottom surface of the element and adhered to a support such as a metal stage, the light extraction surface side depends on the thickness of the metal paste layer interposed between the bottom surface of the element and the support surface. The height position of the upper surface of the element on which the electrode is formed may vary. For example, when wire bonding to the light extraction surface side electrode is performed automatically, there may be a problem in obtaining a uniform bonding state. . However, according to the above configuration, if the main back surface of the residual substrate portion is brought into close contact with the support surface and is adhered by the metal paste layer filled in the notch portion, the thickness of the residual substrate portion can be controlled by controlling the thickness. The thickness of the paste layer can be made uniform, and variations in the position in the height direction of the light extraction surface side electrode after bonding can be reduced (this effect is also exhibited in the first embodiment).

以上の構成において金属反射部は、切欠き部の底面に成膜された金属膜とすることができる。この構成は、蒸着やスパッタなどの成膜工程が必要になるが、金属膜の平滑性が高いので、より反射率の高い金属反射部を得ることができる。なお、金属膜は、切欠き部の底面とともに残留基板部の主裏面も一括して覆うものとすれば、形成が容易である。この場合、残留基板部の主裏面の面積が主表面の面積よりも小となるように、該残留基板部の周側面を傾斜面として形成し、該金属膜を、残留基板部の主裏面及び周側面と、切欠き部底面とを一体的に覆うものとすることができる。このようにすると、蒸着やスパッタ等の指向性の強い成膜法により金属膜を形成する場合、残留基板部の周側面を上記のような傾斜面としておくことで、該周側面にも金属膜を十分な厚さにて形成することができる。該構成は、残留基板部と切欠き部底面とを覆う金属膜を、面内方向の一体の給電路として利用する場合に、特に有効である。 In the above configuration, the metal reflecting portion can be a metal film formed on the bottom surface of the notch portion. This configuration requires a film forming process such as vapor deposition or sputtering, but since the metal film has high smoothness, a metal reflecting portion with higher reflectivity can be obtained. The metal film can be easily formed if it covers the main back surface of the remaining substrate portion together with the bottom surface of the notch portion. In this case, the peripheral side surface of the residual substrate portion is formed as an inclined surface so that the area of the main back surface of the residual substrate portion is smaller than the area of the main surface , and the metal film is formed on the main back surface and the residual substrate portion. The peripheral side surface and the notch bottom surface can be integrally covered. In this case, when a metal film is formed by a highly directional film forming method such as vapor deposition or sputtering, the peripheral side surface of the remaining substrate portion is inclined as described above, so that the metal film is also formed on the peripheral side surface. Can be formed with a sufficient thickness. This configuration is particularly effective when a metal film that covers the remaining substrate portion and the bottom surface of the notch portion is used as an integral power supply path in the in-plane direction.

一方、金属反射部は切欠き部内に充填された金属ペースト層とすることもできる。この方法によると、金属ペーストを塗布することにより切欠き部内に金属反射部を簡単に形成することができる。さらに、切欠き部の内側空間を、伝熱性の高い金属ペーストで充填することにより、発光層部の放熱を促進でき、通電による発光層部の温度上昇が抑制されるので、素子の長寿命化を図ることができる。この場合、残留基板部の主裏面を、切欠き部内を充填する金属ペースト層の主裏面とともに第一態様と同様の放熱用金属部材により覆うことができる。放熱用金属部材を設けることにより発光層部の放熱をさらに促進することができる。 On the other hand, the metal reflection part may be a metal paste layer filled in the notch part. According to this method, the metal reflecting portion can be easily formed in the notch by applying the metal paste. Furthermore, by filling the inner space of the notch with a highly heat conductive metal paste, heat dissipation of the light emitting layer can be promoted, and the temperature rise of the light emitting layer due to energization is suppressed, thus extending the life of the device Can be achieved. In this case, the main back surface of the residual substrate portion can be covered with the heat dissipating metal member similar to the first embodiment together with the main back surface of the metal paste layer filling the notch portion. By providing the metal member for heat dissipation, heat dissipation of the light emitting layer portion can be further promoted.

（第三態様）
残留基板部の一部を切り欠いて切欠き部を形成し、該切欠き部の底面を主光取出面とするとともに、発光層部へ発光駆動電圧を印加するための光取出側電極を残留基板部の主裏面を覆って形成したことを特徴とする。 (Third embodiment)
A part of the residual substrate part is notched to form a notch part, the bottom surface of the notch part is used as a main light extraction surface, and a light extraction side electrode for applying a light emission driving voltage to the light emitting layer part remains. It is characterized by being formed to cover the main back surface of the substrate portion .

特許文献１及び非特許文献１においては、発光層部の基板に面しているのと反対側の主表面（主表面）を光取出面とし、基板が除去された主裏面側は金属層の配置により反射面として利用する、というのが基本的な考え方である。この場合、反射面積をなるべく大きくしたほうが光取出し効率の向上には好都合であるから、基板を一部でも残せばその分だけ反射面積は減少し、しかもそれが光吸収性であることを考えれば、基板の一部を敢えて残すような思想が生まれるはずもなかった。 In Patent Document 1 and Non-Patent Document 1, a main surface opposite to the facing substrate of the light emitting layer portion (main surface) and the light output surface, a main rear surface side of the substrate has been removed in the metal layer The basic idea is to use it as a reflective surface depending on the arrangement. In this case, it is convenient to increase the reflection area as much as possible to improve the light extraction efficiency, so if you leave even a part of the substrate, the reflection area will decrease by that amount, and considering that it is light absorbing The idea of leaving a part of the board was never born.

本発明者らはそこで発想を転換し、発光層部を有する主化合物半導体層の、残留基板部に面している主裏面を主光取出面として利用する構成について検討した。光吸収部として作用する成長用のＧａＡｓ副基板部は、これを除去することで発光層部からの発光光束を取り出すことができる。そして、その副基板部の全てを除去するのではなく、副基板部の一部が主化合物半導体層の主表面上への残留基板部となるように、その一部のみを切り欠くようにすれば、形成される切欠き部の底面を主光取出面として利用することができ、該部分へ向かう発光光束も外部へ取り出すことが可能となるので、光取出し効率を高めることができる。他方、主化合物半導体層の主裏面には、発光駆動用の光取出側電極を形成する必要がある。該光取出側電極の直下領域では、ここに向かう発光光束が存在しても電極に遮られるため、いずれにしろ直接光としては取り出すことができない。そこで、本発明者らは、残留基板部の主裏面を該光取出側電極の形成領域として活用すれば、該残留基板部による光吸収作用を、光取出側電極による光遮断作用により埋没させることができ、その実害を大幅に軽減できることを見出した。この結果、ＧａＡｓからなる残留基板部による、光吸収の影響がそれほど顕著化することがなくなり、ＧａＡｓ特有の物性をむしろ積極利用して、機能的素子構成要素として有効活用するようなことも可能となる。 Therefore, the inventors changed the way of thinking and examined a configuration in which the main back surface of the main compound semiconductor layer having the light emitting layer portion facing the residual substrate portion is used as the main light extraction surface. The growth GaAs sub-substrate portion acting as a light absorbing portion can remove the emitted light flux from the light emitting layer portion by removing it. Then, instead of removing all of the sub-substrate portion, only a part of the sub-substrate portion is cut out so that a portion of the sub-substrate portion becomes a residual substrate portion on the main surface of the main compound semiconductor layer. In this case, the bottom surface of the formed notch can be used as the main light extraction surface, and the emitted light flux toward the portion can be extracted to the outside, so that the light extraction efficiency can be increased. On the other hand, it is necessary to form a light extraction side electrode for driving light emission on the main back surface of the main compound semiconductor layer. In the region immediately below the light extraction side electrode, even if there is a luminous flux directed toward this area, it is blocked by the electrode, so in any case it cannot be extracted as direct light. Therefore, the present inventors use the main back surface of the residual substrate portion as a region for forming the light extraction side electrode, so that the light absorption effect by the residual substrate portion is buried by the light blocking effect by the light extraction side electrode. can be found that the real damage can be greatly reduced. As a result, the effect of light absorption due to the residual substrate portion made of GaAs does not become so noticeable, and it is possible to effectively utilize the physical properties peculiar to GaAs as a functional element component. Become.

上記の光取出側電極には、通電用ワイヤを接合することができる。発光層部と光取出側電極との間に介在する化合物半導体層の厚さが小さい場合（特に、２μｍ以下の場合）、通電用ワイヤを光取出側電極へ接合しようとすると、接合による損傷の影響が発光層部に及びやすく、不良を生じやすい欠点がある。例えばワイヤの接合を、超音波溶接や、これにさらに熱を付加するサーモソニックボンディングにより行なう場合、ボンディングパッド直下の化合物半導体層には、超音波や加熱（さらには加圧）による衝撃応力が集中し、転位などの結晶欠陥が損傷として導入される。その損傷領域が発光層部に及んだ場合、具体的には次のような不具合につながる。
(1)発光輝度の直接的な低下。結晶欠陥による非発光遷移過程の増加が原因として考えられる。
(2)損傷領域が発光層部に及ぶと素子ライフが低下することにつながる。転位の形成された発光層に通電を継続すると、転位に電流が集中して転位の増殖が起こりやすくなり、発光輝度の経時的な劣化を引き起こす。 A current-carrying wire can be joined to the light extraction side electrode. When the thickness of the compound semiconductor layer interposed between the light emitting layer portion and the light extraction side electrode is small (especially in the case of 2 μm or less), if the current-carrying wire is bonded to the light extraction side electrode, There is a defect that the influence is easily exerted on the light emitting layer portion, and a defect is likely to occur. For example, when wire bonding is performed by ultrasonic welding or thermosonic bonding that adds heat to this, impact stress due to ultrasonic waves or heating (and pressurization) is concentrated on the compound semiconductor layer directly under the bonding pad. Then, crystal defects such as dislocations are introduced as damage. When the damaged area reaches the light emitting layer portion, specifically, the following problems are caused.
(1) Direct decrease in emission luminance. This is thought to be due to an increase in the non-luminescent transition process due to crystal defects.
(2) If the damaged region reaches the light emitting layer portion, the device life is reduced. If energization is continued in the light emitting layer in which dislocations are formed, current concentrates on the dislocations, and dislocations are likely to proliferate, which causes deterioration in emission luminance over time.

しかし、光取出側電極の直下に残留基板部が存在していれば、接合時に損傷領域が仮に生じても、その大半は残留基板部内部に留まり、発光層部や電流拡散層等にその影響が及びにくくなり、不良低減を図ることができる。この効果を顕著に達成するには、残留基板部の厚さを３μｍ以上確保しておくことが望ましい。   However, if there is a residual substrate portion directly under the light extraction side electrode, even if a damaged region occurs during bonding, most of it remains inside the residual substrate portion, and this affects the light emitting layer portion, current diffusion layer, etc. This makes it difficult to reduce defects. In order to achieve this effect remarkably, it is desirable to secure a thickness of the residual substrate portion of 3 μm or more.

次に、光取出側電極の直下領域では、発光層部をいくら光らせても発光光束の多くが光取出側電極に遮られ、外部に効率よく取り出すことができない。従って、光取出側電極の直下領域にて通電電流をなるべく少なくすることが望ましくなる。具体的には次のような構成を採用できる。すなわち、光取出側電極を、残留基板部を覆う主電極と、該主電極に導通するとともに切欠き部の底面のうち残留基板部の周囲に位置する一部領域を覆う副電極とを有するものとして形成する。また、接触抵抗低減用の接合合金化層を、副電極と接する切欠き部の底面領域に形成する。これにより、光取出側電極は残留基板部外の接合合金化層を介して化合物半導体層と導通する。そして、該構造を前提として、第一の態様では、残留基板部を、発光層部にてｐ−ｎ接合を形成するｐ型層部とｎ型層部とのうち、該残留基板部に近い側のものと逆の導電型を有する電流阻止層として構成する。また第二の態様では、残留基板部を、発光層部にてｐ−ｎ接合を形成するｐ型層部とｎ型層部とのうち、該残留基板部に近い側のものと同一の導電型を有するものとし、かつ、発光層部と残留基板部との間に、残留基板部を被覆する形で、該残留基板部と逆の導電型を有する化合物半導体からなる反転層部を介挿する。いずれの構成においても、残留基板部と発光層部との間には、素子に発光駆動電圧（つまり、発光層部をなすｐ−ｎ接合部に対し順方向となる電圧）を印加したとき、逆バイアス状態となる反転ｐ−ｎ接合部が介在することになるので、発光光束が遮光されやすい光取出側電極直下領域への分配電流（すなわち発光）が抑制され、光取出し効率のさらなる向上に寄与する。   Next, in the region immediately below the light extraction side electrode, no matter how much the light emitting layer portion is illuminated, most of the luminous flux is blocked by the light extraction side electrode and cannot be efficiently extracted outside. Therefore, it is desirable to reduce the energization current as much as possible in the region immediately below the light extraction side electrode. Specifically, the following configuration can be adopted. That is, the light extraction side electrode has a main electrode that covers the residual substrate portion, and a sub-electrode that is connected to the main electrode and covers a partial region of the bottom surface of the notch portion that is located around the residual substrate portion Form as. Further, a bonding alloying layer for reducing contact resistance is formed in the bottom surface region of the notch that is in contact with the sub electrode. Thereby, the light extraction side electrode is electrically connected to the compound semiconductor layer through the bonding alloyed layer outside the residual substrate portion. And on the premise of this structure, in the first aspect, the residual substrate portion is close to the residual substrate portion among the p-type layer portion and the n-type layer portion that form a pn junction in the light emitting layer portion. It is configured as a current blocking layer having a conductivity type opposite to that on the side. In the second embodiment, the residual substrate portion has the same conductivity as that of the p-type layer portion and the n-type layer portion that form a pn junction in the light emitting layer portion, closer to the residual substrate portion. An inversion layer portion made of a compound semiconductor having a conductivity type opposite to that of the residual substrate portion is interposed between the light emitting layer portion and the residual substrate portion so as to cover the residual substrate portion. To do. In any configuration, when a light emission driving voltage (that is, a voltage in a forward direction with respect to a pn junction portion forming the light emitting layer portion) is applied between the residual substrate portion and the light emitting layer portion, Since the reverse pn junction that is in the reverse bias state is interposed, the distribution current (that is, light emission) to the region immediately below the light extraction side electrode where the luminous flux is likely to be blocked is suppressed, and the light extraction efficiency is further improved. Contribute.

また、光取出側電極が、残留基板部を覆う主電極と、該主電極に導通するとともに切欠き部の底面のうち残留基板部の周囲に位置する一部領域を覆う副電極とを有し、接触抵抗低減用の接合合金化層が、主電極と接する残留基板部には形成されず、副電極と接する切欠き部の底面領域には形成される構成とすることもできる。光取出側電極に上記のような副電極を設け、光取出側電極と主化合物半導体層との電気的な接続を、残留基板部外の切欠き部底面に形成された接合合金化層との間でのみ確保することで、発光駆動時における残留基板部での電流密度を効果的に低減できる（この場合、残留基板部と主化合物半導体層との間に前述のような反転ｐ−ｎ接合部が特に形成されていなくともよい）。また、残留基板部を覆う主電極は面積を比較的大きくできるので、通電用ワイヤの接続も容易である。主電極は、残留基板部の周側面を覆う部分にて副電極と接続され、通電用ワイヤから接合合金化層への給電部としての役割を果たす。通電用ワイヤの接合時に、残留基板部が損傷吸収効果をもたらすことは既に説明した通りである。   Further, the light extraction side electrode has a main electrode that covers the residual substrate portion, and a sub-electrode that is connected to the main electrode and covers a part of the bottom surface of the notch portion that is located around the residual substrate portion. The bonding alloying layer for reducing the contact resistance may not be formed on the remaining substrate portion in contact with the main electrode, but may be formed in the bottom surface region of the notch portion in contact with the sub electrode. The sub electrode as described above is provided on the light extraction side electrode, and the electrical connection between the light extraction side electrode and the main compound semiconductor layer is made with the bonding alloyed layer formed on the bottom surface of the notch portion outside the residual substrate portion. By securing only the gap between the remaining substrate portion and the main compound semiconductor layer in this case, the current density in the remaining substrate portion at the time of light emission driving can be effectively reduced. Part may not be formed in particular). In addition, since the main electrode covering the residual substrate portion can have a relatively large area, it is easy to connect the energizing wires. The main electrode is connected to the sub electrode at a portion covering the peripheral side surface of the residual substrate portion, and serves as a power feeding portion from the energizing wire to the bonded alloyed layer. As described above, the residual substrate portion provides a damage absorbing effect when the energizing wire is joined.

逆に、残留基板部の主裏面には、光取出側電極との接触抵抗を減ずるための接合合金化層を形成することもできる。ＧａＡｓはバンドギャップエネルギーが小さく耐酸化性にも優れるので、他のＩＩＩ−Ｖ族化合物半導体（例えば発光層部を形成するＡｌＧａＩｎＰや、電流拡散層を形成するＧａＰ、ＡｌＧａＡｓ、ＧａＡｓＰあるいはＧａＩｎＰなど）と比較して、金属電極との間で格段にオーミックコンタクトを取りやすい利点がある。従って、該ＧａＡｓからなる残留基板部を接合合金化層の形成領域として利用することで、素子の光取出側電極との接触抵抗を効果的に低減でき、ひいては素子の順方向電圧を低減できるようになる。 Conversely, a bonding alloyed layer for reducing the contact resistance with the light extraction side electrode can be formed on the main back surface of the residual substrate portion. Since GaAs has a small band gap energy and excellent oxidation resistance, other III-V group compound semiconductors (for example, AlGaInP forming a light emitting layer part, GaP, AlGaAs, GaAsP, or GaInP forming a current diffusion layer) and the like In comparison, there is an advantage that an ohmic contact can be easily made with the metal electrode. Therefore, by using the residual substrate portion made of GaAs as the formation region of the bonding alloying layer, the contact resistance with the light extraction side electrode of the element can be effectively reduced, and consequently the forward voltage of the element can be reduced. become.

次に、第三態様の発光素子においては、発光層部の主表面側に、発光層部からの発光光束のピーク波長に相当する光量子エネルギーよりも大きなバンドギャップエネルギーを有するＩＩＩ−Ｖ族化合物半導体からなる厚さ１０μｍ以上の透明厚膜半導体層を設けることができる。このような透明厚膜半導体層を設けることで、薄い発光層部に対し面内方向により均一に発光駆動電流を供給でき、該透明厚膜半導体層の側面からの取出光束も増加するので、素子全体としての光取出し効率を高めることができる。また、透明厚膜半導体層が素子全体の補強効果を高め、素子製造時のハンドリングがより容易になる。さらに、該透明厚膜半導体層の側で発光素子を、金属ペースト層を介して金属ステージ上に接着する構成とする場合、接着時に金属ペースト層がつぶれ変形して主化合物半導体層の周側面側に這い上がることがある。この這い上がった金属ペーストが発光層部のｐ−ｎ接合部側面に達すると、ｐ−ｎ接合部が短絡するなどの不具合を生ずることがある。しかし、上記のように、この接着側に設ける透明厚膜半導体層の厚さを４０μｍ以上（上限値に制限はないが、例えば２００μｍ以下である）に確保すれば、仮に金属ペーストが這い上がってもｐ−ｎ接合部にまで達する確率は小さくなり、上記短絡等の不具合を効果的に防止できる。 Next, in the light emitting device of the third aspect, a group III-V compound semiconductor having a band gap energy larger than the photon energy corresponding to the peak wavelength of the luminous flux from the light emitting layer portion on the main surface side of the light emitting layer portion. A transparent thick film semiconductor layer having a thickness of 10 μm or more can be provided. By providing such a transparent thick film semiconductor layer, a light emission drive current can be supplied uniformly to the thin light emitting layer portion in the in-plane direction, and the extracted light flux from the side surface of the transparent thick film semiconductor layer also increases. The overall light extraction efficiency can be increased. Further, the transparent thick film semiconductor layer enhances the reinforcing effect of the entire device, and handling during device manufacture becomes easier. Further, when the light emitting element is bonded to the metal stage via the metal paste layer on the transparent thick film semiconductor layer side, the metal paste layer is crushed and deformed during bonding, and the peripheral side surface side of the main compound semiconductor layer May crawl up. When this scooped up metal paste reaches the pn junction side surface of the light emitting layer, there may be a problem such as a short circuit of the pn junction. However, as described above, if the thickness of the transparent thick film semiconductor layer provided on the bonding side is ensured to be 40 μm or more (the upper limit is not limited, but is, for example, 200 μm or less), the metal paste will rise. However, the probability of reaching the pn junction is reduced, and the above short circuit and other problems can be effectively prevented.

また、主化合物半導体層は、残留基板部と発光層部との間に配置されるとともに、透明厚膜半導体層よりも薄い化合物半導体層よりなる補助電流拡散層を有するものとして構成できる。これにより、切欠き部底面部への電流拡散効果が高められ、発光層部の該切欠き部に対応した領域（つまり、主光取出面）への分配電流が増加するので、切欠き部底面から取り出される発光光束をより増加することができる。また、光取出側電極に通電用ワイヤを接合する場合は、この補助電流拡散層は前述の残留基板部とともに、接合による損傷の影響が発光層部へ及ぶことを抑制するクッション層としての機能も果たしうる。   The main compound semiconductor layer can be configured to have an auxiliary current diffusion layer made of a compound semiconductor layer that is disposed between the residual substrate portion and the light emitting layer portion and is thinner than the transparent thick film semiconductor layer. As a result, the current spreading effect to the bottom surface of the cutout portion is enhanced, and the distribution current to the region corresponding to the cutout portion of the light emitting layer portion (that is, the main light extraction surface) is increased. The luminous flux extracted from can be further increased. In addition, when a current-carrying wire is bonded to the light extraction side electrode, this auxiliary current diffusion layer functions as a cushion layer that suppresses the influence of damage caused by bonding to the light-emitting layer portion together with the above-described residual substrate portion. It can be done.

ただし、上記構成では、発光層部の主裏面側に設ける補助電流拡散の厚さは小さくなるので、電流拡散効果は透明厚膜半導体層よりも劣る。そこで、これを補うために光取出側電極を、残留基板部の主裏面及び周側面とを覆う主電極と、切欠き部の底面をなす補助電流拡散層の主裏面の一部領域を覆うとともに、主電極の外周縁から延出する線状の副電極とを有するものとして構成することが有効である。上記のような副電極を設けることで、駆動電圧を印加した際に、主光取出面内の電界分布の偏りを軽減することができ、主光取出面全体に、より一様に電圧印加することができるので、電流拡散効果を高めることがでできる。また、主電極の直下に位置する残留基板部を前述のごとく電流阻止層として機能させれば、主電極の直下に向かう電流を遮断でき、主光取出面をなす主電極の背景領域への電流分配量を増加できるので、光取出し効率を高めることができる。この場合、前述のごとく、残留基板部の主裏面の面積が主表面の面積よりも小となるように、該残留基板部の周側面を傾斜面として形成し、光取出側電極をなす主電極と副電極を一体の金属膜として形成すれば、主電極と副電極との電気的導通をより確実なものとすることができる。 However, in the above configuration, since the thickness of the auxiliary current diffusion provided on the main back surface side of the light emitting layer portion is small, the current diffusion effect is inferior to that of the transparent thick film semiconductor layer. Therefore, to compensate for this, the light extraction side electrode covers the main electrode that covers the main back surface and the peripheral side surface of the residual substrate portion, and a partial region of the main back surface of the auxiliary current diffusion layer that forms the bottom surface of the notch portion. It is effective to have a linear sub-electrode extending from the outer peripheral edge of the main electrode. By providing the sub-electrode as described above, the bias of the electric field distribution in the main light extraction surface can be reduced when a driving voltage is applied, and the voltage is applied more uniformly across the main light extraction surface. Therefore, the current spreading effect can be enhanced. In addition, if the residual substrate portion located immediately below the main electrode functions as a current blocking layer as described above, the current flowing directly below the main electrode can be cut off, and the current to the background area of the main electrode forming the main light extraction surface can be cut off. Since the amount of distribution can be increased, the light extraction efficiency can be increased. In this case, as described above, the main electrode forming the light extraction side electrode is formed by forming the peripheral side surface of the residual substrate portion as an inclined surface so that the area of the main back surface of the residual substrate portion is smaller than the area of the main surface. And the sub-electrode are formed as an integral metal film, the electrical continuity between the main electrode and the sub-electrode can be made more reliable.

発光層部が、残留基板部に近い側から第一導電型クラッド層、活性層及び第二導電型クラッド層がこの順序で積層されたダブルへテロ構造を有し、かつ、発光層部上に上記のような透明厚膜半導体層を設ける場合、主化合物半導体層の主裏面から少なくとも活性層の主表面までの区間を、主裏面の一部領域において厚さ方向に切り欠くことにより電極用切欠き部を形成し、その電極用切欠き部の底面に異極性電極（光取出側電極とは異極性となる側の電極）を配置することもできる（以下、同面側電極取出構造ともいう）。この構成は、主化合物半導体の主裏面側の一部が異極性電極の形成スペースとして消費される難点はあるが、発光駆動用の電極を同一主表面側に形成できる利点を生ずる。 The light emitting layer portion has a double hetero structure in which the first conductive type cladding layer, the active layer, and the second conductive type cladding layer are laminated in this order from the side close to the residual substrate portion, and on the light emitting layer portion. when providing a transparent thick semiconductor layer as described above, the main compound section from the main back surface of the semiconductor layer to the main surface of at least the active layer, the electrode for switching by cutting in the thickness direction in a partial area of the main back surface A notched portion can be formed, and a different polarity electrode (an electrode having a different polarity from the light extraction side electrode) can be disposed on the bottom surface of the electrode notch portion (hereinafter also referred to as the same surface side electrode extraction structure). ). Although this configuration has a drawback that a part of the main back surface side of the main compound semiconductor is consumed as a space for forming the different polarity electrode, there is an advantage that an electrode for light emission driving can be formed on the same main surface side.

例えば、ＩＩＩ族窒化物系の青色発光素子は、ＩＩＩ族窒化物のエピタキシャル成長用の基板としてサファイア基板が使用されるが、サファイア基板は絶縁体であり、しかもエッチング等による除去も困難なため、発光層部の下に該サファイア基板を残した形で素子化されるケースが多い。この場合、発光層部とサファイア基板との間に導電性の電極取出層を形成し、発光層部の一部を切り欠いて電極取出層を露出させ、ここに異極性電極を形成することが必須となる。こうした窒化物系青色発光素子のように、製造工程上、同面側電極取出構造を取らざるを得ない発光素子と、第三態様の発光素子とを組み合わせて一体の発光モジュールを構成したい場合に、第三態様の発光素子に敢えて上記同面側電極取出構造を採用すれば、該別種の発光素子の光取出側電極又は異極性電極のうち、接地側となる電極を共通結線することができ、ワイヤボンディング等のアセンブリ工程を簡略化できる利点がある。また、ＲＧＢフルカラー発光素子モジュールのように、この種の発光素子を３以上組み合わせてモジュール化する場合、それらの素子の接地側の電極電位は全て等しくなるため、これら電極をワイヤにより順次連結し、その末端に位置する電極のみ、素子チップを接着するステージ側のカソード端子に接続する構成が可能となり、ステージ側のカソード端子の面積縮小、ひいてはモジュールの小型化にも寄与する。   For example, a group III nitride blue light-emitting device uses a sapphire substrate as a substrate for epitaxial growth of group III nitride, but the sapphire substrate is an insulator and is difficult to remove by etching or the like. In many cases, the sapphire substrate is left under the layer portion to form an element. In this case, a conductive electrode extraction layer is formed between the light emitting layer portion and the sapphire substrate, a part of the light emitting layer portion is notched to expose the electrode extraction layer, and a different polarity electrode is formed here. Required. When such a nitride-based blue light-emitting element is combined with the light-emitting element of the third embodiment in combination with the light-emitting element that has to have the same-surface-side electrode extraction structure in the manufacturing process, and to form an integrated light-emitting module If the same-surface-side electrode extraction structure is used for the light-emitting element of the third aspect, the ground-side electrode among the light-extraction-side electrode or the different-polarity electrode of the different type of light-emitting element can be connected in common. There is an advantage that the assembly process such as wire bonding can be simplified. In addition, when a module is formed by combining three or more light emitting elements of this type as in the RGB full color light emitting element module, since the electrode potentials on the ground side of these elements are all equal, these electrodes are sequentially connected by wires, Only the electrode located at the end can be connected to the cathode terminal on the stage side to which the element chip is bonded, which contributes to the reduction of the area of the cathode terminal on the stage side and the miniaturization of the module.

さらに、第三態様の発光素子の場合、発光層部が結合される基板が絶縁性基板でなく、導電性の透明厚膜半導体層であるからこれを電極取出層として活用できる。透明厚膜半導体層は層厚が大きいため（１０μｍ以上）、サファイア基板を用いたＩＩＩ族窒化物発光素子の電極取出層のような薄いエピタキシャル層よりもシート抵抗の低減が容易であり、素子の順方向電圧の増加も招きにくい。さらに、サファイア基板上の発光層部は、例えば素子チップを接着する金属製のステージを使用する場合、該ステージからサファイア基板によって絶縁分離されるため、素子チップの浮遊容量が増大し、発光層部の帯電により実効的な発光駆動電圧が低下したり、あるいはスパークにより素子寿命が低下したりするなどの不具合を生ずることもある。しかし、基板に相当する部分が上記のように導電性の透明厚膜半導体層にて構成されていれば、該透明厚膜半導体層が静電気の放電路として機能するので、発光層部の帯電が大幅に軽減され、上記の不具合を解消することができる。この場合、複数個連結する同面側電極取出構造の発光素子の一部が、上記のような絶縁基板付き素子とされていても、残りの素子の一部が第三態様の上記構成の発光素子にて構成されていれば、接地共通結線化により、絶縁基板付きの素子に帯電する静電気も、第三態様の素子の透明厚膜半導体層を介して放電できる利点もある。   Furthermore, in the case of the light emitting device of the third aspect, since the substrate to which the light emitting layer portion is bonded is not an insulating substrate but a conductive transparent thick film semiconductor layer, it can be utilized as an electrode extraction layer. Since the transparent thick film semiconductor layer has a large layer thickness (10 μm or more), the sheet resistance can be reduced more easily than a thin epitaxial layer such as an electrode extraction layer of a group III nitride light emitting device using a sapphire substrate. It is also difficult to increase the forward voltage. Furthermore, the light emitting layer portion on the sapphire substrate is insulated and separated from the stage by the sapphire substrate when using, for example, a metal stage to which the device chip is bonded. In some cases, the effective light emission driving voltage may be reduced due to charging, or the device life may be reduced due to sparking. However, if the portion corresponding to the substrate is composed of the conductive transparent thick film semiconductor layer as described above, the transparent thick film semiconductor layer functions as a discharge path for static electricity, so that the light emitting layer portion is not charged. It is greatly reduced and the above problems can be solved. In this case, even if a part of the light emitting elements having the same-surface-side electrode extraction structure connected to each other is an element with an insulating substrate as described above, a part of the remaining elements are light emitting devices having the above-described configuration of the third aspect. If it is constituted by an element, there is an advantage that the static electricity charged in the element with the insulating substrate can be discharged through the transparent thick film semiconductor layer of the element of the third aspect by common grounding.

次に、第四態様の発光素子は、
発光層部を有した主化合物半導体層が副基板部の主表面上にエピタキシャル成長され、残留基板部の一部に切欠き部が形成され、発光層部へ発光駆動電圧を印加するための第一電極部が残留基板部の主裏面を覆って形成される一方、
発光層部が、残留基板部に近い側から第一導電型クラッド層、活性層及び第二導電型クラッド層がこの順序で積層されたダブルへテロ構造を有してなり、発光層部の主表面側には、発光層部からの発光光束のピーク波長に相当する光量子エネルギーよりも大きなバンドギャップエネルギーを有するＩＩＩ−Ｖ族化合物半導体からなる透明半導体層が形成されてなり、さらに、主化合物半導体層の主裏面側から少なくとも活性層の主表面までの区間を、主裏面の一部領域において主化合物半導体層の主裏面側から厚さ方向に切り欠くことにより電極用切欠き部が形成され、その電極用切欠き部の底面に第一電極部とは異極性となる第二電極部が配置されるとともに、透明半導体層の主表面が主光取出面とされることを特徴とする。 Next , the light-emitting element of the fourth aspect is
A main compound semiconductor layer having a light emitting layer portion is epitaxially grown on the main surface of the sub-substrate portion, a notch portion is formed in a part of the remaining substrate portion, and a first light source for applying a light emission driving voltage to the light emitting layer portion. While the electrode part is formed covering the main back surface of the residual substrate part ,
Emitting layer portion, the first-conductivity-type cladding layer from the side closer to the residual substrate portion, the active layer and the second conductivity type cladding layer is a double-hetero structure laminated in this order, the main light emitting layer portion On the surface side, a transparent semiconductor layer made of a III-V group compound semiconductor having a band gap energy larger than the photon energy corresponding to the peak wavelength of the luminous flux from the light emitting layer portion is formed. the section from the main back surface side of the layer to the main surface of at least the active layer, notch electrode is formed by cutting in the thickness direction from the main back surface side of the main compound semiconductor layer in some area of the main rear surface, A second electrode portion having a different polarity from the first electrode portion is disposed on the bottom surface of the electrode cutout portion, and the main surface of the transparent semiconductor layer is a main light extraction surface.

この構成は、同面側電極取出構造を採用した第三態様の発光素子の上下を反転し、透明半導体層の主表面側に電極を形成せず、該主表面側から発光光束を主に取り出すようにしたものに相当する。同面側電極取出構造では、２つの電極を同一面側に形成する必要があるので、電極形成スペースも限られたものとなる。第四態様によると、そのうちの第一電極部を残留基板部の主裏面に形成する。ＧａＡｓはバンドギャップエネルギーが小さく耐酸化性にも優れるので、他のＩＩＩ−Ｖ族化合物半導体（例えば発光層部を形成するＡｌＧａＩｎＰや、電流拡散層を形成するＧａＰ、ＡｌＧａＡｓ、ＧａＡｓＰあるいはＧａＩｎＰなど）と比較して、金属電極との間で格段にオーミックコンタクトを取りやすい利点がある。従って、該ＧａＡｓからなる残留基板部を第一電極部の形成領域として利用することで、素子の第一電極部との接触抵抗を効果的に低減でき、素子の順方向電圧を低減できるようになる。そして、電極形成されない透明半導体層の主表面が主光取出面となるので、該主光取出面の面積が拡大され、光取出し効率が大幅に向上する。さらに、主化合物半導体層の主裏面側に全ての電極が形成されるので、例えば素子チップを基板上に面実装する構成も容易となり、素子チップのアセンブリ工程の簡略化にも寄与する。 This configuration inverts the top and bottom of the third aspect of the light emitting device employing the same side electrode lead-out structure, without forming an electrode on the main surface of the transparent semiconductor layer, mainly emitted light flux from the main surface side It corresponds to what you did. In the same surface side electrode extraction structure, two electrodes need to be formed on the same surface side, so that an electrode forming space is limited . According to the fourth aspect, the first electrode portion is formed on the main back surface of the residual substrate portion. Since GaAs has a small band gap energy and excellent oxidation resistance, other III-V group compound semiconductors (for example, AlGaInP forming a light emitting layer part, GaP, AlGaAs, GaAsP, or GaInP forming a current diffusion layer) and the like In comparison, there is an advantage that an ohmic contact can be easily made with the metal electrode. Therefore, by utilizing the residual substrate portion made of GaAs as the formation region of the first electrode portion, the contact resistance with the first electrode portion of the element can be effectively reduced, and the forward voltage of the element can be reduced. Become. And since the main surface of the transparent semiconductor layer in which an electrode is not formed becomes a main light extraction surface, the area of the main light extraction surface is enlarged, and the light extraction efficiency is greatly improved. Furthermore, since all the electrodes are formed on the main back surface side of the main compound semiconductor layer, for example, a configuration in which the element chip is surface-mounted on the substrate is facilitated, which contributes to simplification of the assembly process of the element chip.

（第一態様）
以下、第一態様の実施形態を添付の図面を用いて説明する。
図１は第一態様の一例である発光素子１００を模式的に示すものである。発光素子１００は、発光層部２４を有した主化合物半導体層４０が残留基板部１の主表面上に形成されている。そして、主化合物半導体層４０の主表面側に主光取出面ＥＡが形成されるとともに、発光層部２４に発光駆動電圧を印加するための光取出側電極９が主化合物半導体層４０の主表面の一部を覆うように形成されている。そして、残留基板部１を一部切り欠く形で該残留基板部１の主裏面に開口する切欠き部としての開口部１ｊが形成され、該開口部１ｊの周縁に残された残留基板部１が発光層部２４への剛性を付与している。そして、開口部１ｊの内部に、発光層部２４からの発光光束を反射させる反射部１７ｂが設けられ、その反射光束ＲＢが発光層部２４からの直接光束ＤＢと重畳されて主光取出面ＥＡから取り出される。 (First aspect)
Hereinafter , embodiments of the first aspect will be described with reference to the accompanying drawings.
FIG. 1 schematically shows a light emitting device 100 as an example of the first embodiment. In the light emitting element 100, the main compound semiconductor layer 40 having the light emitting layer portion 24 is formed on the main surface of the residual substrate portion 1. A main light extraction surface EA is formed on the main surface side of the main compound semiconductor layer 40, and the light extraction side electrode 9 for applying a light emission driving voltage to the light emitting layer portion 24 is the main surface of the main compound semiconductor layer 40. It is formed so as to cover a part of. Then, an opening 1j is formed as a notch opening in the main back surface of the residual substrate 1 in a form in which the residual substrate 1 is partially cut out, and the residual substrate 1 left on the periphery of the opening 1j. Provides rigidity to the light emitting layer portion 24. A reflection portion 17b that reflects the emitted light beam from the light emitting layer portion 24 is provided inside the opening 1j, and the reflected light beam RB is superimposed on the direct light beam DB from the light emitting layer portion 24 to be superimposed on the main light extraction surface EA. Taken from.

発光層部２４は、ノンドープ（ＡｌｘＧａ１−ｘ）ｙＩｎ１−ｙＰ（ただし、０≦ｘ≦０．５５，０．４５≦ｙ≦０．５５）混晶からなる活性層５を、第二導電型クラッド層、本実施形態ではｐ型（ＡｌｚＧａ１−ｚ）ｙＩｎ１−ｙＰ（ただしｘ＜ｚ≦１）からなるｐ型クラッド層６と、前記第二導電型クラッド層とは異なる第一導電型クラッド層、本実施形態ではｎ型（ＡｌｚＧａ１−ｚ）ｙＩｎ１−ｙＰ（ただしｘ＜ｚ≦１）からなるｎ型クラッド層４とにより挟んだ構造を有し、活性層５の組成に応じて、発光波長を、緑色から赤色領域（発光波長（ピーク発光波長）が５５０ｎｍ以上６７０ｎｍ以下）にて調整できる。発光素子１００においては、光取出側電極９側にｐ型ＡｌＧａＩｎＰクラッド層６が配置されており、残留基板部１側にｎ型ＡｌＧａＩｎＰクラッド層４が配置されている。従って、通電極性は光取出側電極９が正である。なお、ここでいう「ノンドープ」とは、「ドーパントの積極添加を行なわない」との意味であり、通常の製造工程上、不可避的に混入するドーパント成分の含有（例えば１０１３〜１０１６／ｃｍ３程度を上限とする）をも排除するものではない。また、残留基板部１はＧａＡｓ単結晶からなる。 The light emitting layer portion 24 includes the active layer 5 made of a non-doped (Al x Ga 1-x ) y In 1-y P (where 0 ≦ x ≦ 0.55, 0.45 ≦ y ≦ 0.55) mixed crystal. , the second-conductivity-type cladding layer, a p-type cladding layer 6 made of p-type (Al z Ga 1-z) y in 1-y P ( where, x <z ≦ 1) in the present embodiment, the second conductive type first-conductivity-type cladding layer different from the clad layer, in this embodiment interposed by an n-type (Al z Ga 1-z) y in 1-y P ( except x <z ≦ 1) n-type cladding layer 4 made of According to the composition of the active layer 5, the emission wavelength can be adjusted in the green to red region (the emission wavelength (peak emission wavelength) is 550 nm or more and 670 nm or less). In the light emitting element 100, the p-type AlGaInP clad layer 6 is disposed on the light extraction side electrode 9 side, and the n-type AlGaInP clad layer 4 is disposed on the residual substrate portion 1 side. Therefore, the light extraction side electrode 9 is positive in the energization polarity. The term “non-doped” as used herein means “does not actively add a dopant”, and contains a dopant component inevitably mixed in a normal manufacturing process (for example, 10 13 to 10 16 / cm 3). It is not excluded that the upper limit is about 3 ). The residual substrate portion 1 is made of GaAs single crystal.

また、主化合物半導体層４０においては、発光層部２４の主表面上に、ＧａＰ（あるいはＧａＡｓＰやＡｌＧａＡｓでもよい）よりなる電流拡散層２０が形成され、該電流拡散層２０の主表面の略中央に前述の光取出側電極９（例えばＡｕ電極）が形成されている。電流拡散層２０は、光取出側電極９との間に接合合金化層９ａを介してオーミック接触が形成できる程度に有効キャリア濃度（従って、ｐ型ドーパント濃度）が高められている（例えばｐ型クラッド層６と同等以上であって２×１０１８／ｃｍ３以下）。電流拡散層２０の主表面における、光取出側電極９の周囲の領域が主光取出面ＥＡをなす。電流拡散層２０は、例えば１０μｍ以上２００μｍ以下（好ましくは４０μｍ以上２００μｍ以下）の厚膜に形成されることで、層側面からの取出光束も増加させ、発光素子全体の輝度（積分球輝度）を高める役割も担う。また、電流拡散層２０は、発光層部２４からの発光光束のピーク波長に相当する光量子エネルギーよりも大きなバンドギャップエネルギーを有するＩＩＩ−Ｖ族化合物半導体にて構成することで、発光光束に対する吸収も抑制されている。なお、光取出側電極９と電流拡散層２０との間には、両者の接触抵抗を減ずるための接合合金化層９ａが、例えばＡｕＢｅ合金等を用いて形成されている。他方、残留基板部１側においては、開口部１ｊが該基板部１を厚さ方向に貫通して形成され、主化合物半導体層４０の主裏面、ここでは発光層部２４（ｎ型クラッド層４）の主裏面が開口部１ｊに露出している。 In the main compound semiconductor layer 40, a current diffusion layer 20 made of GaP (or GaAsP or AlGaAs may be used) is formed on the main surface of the light emitting layer portion 24, and approximately the center of the main surface of the current diffusion layer 20. The above-described light extraction side electrode 9 (for example, an Au electrode) is formed. The current diffusion layer 20 has an effective carrier concentration (and hence a p-type dopant concentration) increased to such an extent that an ohmic contact can be formed between the current extraction layer 9 and the light extraction side electrode 9 via the bonding alloying layer 9a (for example, p-type dopant concentration). It is equal to or more than that of the cladding layer 6 and 2 × 10 18 / cm 3 or less). A region around the light extraction side electrode 9 on the main surface of the current diffusion layer 20 forms a main light extraction surface EA. The current diffusion layer 20 is formed in a thick film of, for example, 10 μm or more and 200 μm or less (preferably 40 μm or more and 200 μm or less), thereby increasing the extracted light flux from the side surface of the layer and increasing the luminance (integrated sphere luminance) of the entire light emitting element. It also plays a role to raise. Further, the current spreading layer 20 is made of a III-V group compound semiconductor having a band gap energy larger than the photon energy corresponding to the peak wavelength of the luminous flux from the light emitting layer portion 24, thereby absorbing the luminous flux. It is suppressed. In addition, between the light extraction side electrode 9 and the current diffusion layer 20, a bonding alloying layer 9a for reducing the contact resistance between the two is formed using, for example, an AuBe alloy. On the other hand, on the residual substrate portion 1 side, an opening 1j is formed so as to penetrate the substrate portion 1 in the thickness direction, and the main back surface of the main compound semiconductor layer 40, here the light emitting layer portion 24 (n-type cladding layer 4). the main back surface is exposed to the opening portion 1j of).

上記の開口部１ｊは、光取出側電極９の直下領域ＳＡと重なる形で形成されている。本実施形態では、光取出側電極９の直下領域ＳＡが開口部１ｊの内側に包含され、直下領域ＳＡの全体が開口部１ｊの領域と重なっている。そして、該直下領域ＳＡにおいて、主化合物半導体層４０と反射部１７ｂとの接触抵抗が、主化合物半導体層４０と残留基板部１との接触抵抗よりも高く設定されている。   The opening 1j is formed so as to overlap the region SA directly below the light extraction side electrode 9. In the present embodiment, the region SA directly below the light extraction side electrode 9 is included inside the opening 1j, and the entire region SA directly overlaps the region of the opening 1j. In the region SA immediately below, the contact resistance between the main compound semiconductor layer 40 and the reflecting portion 17 b is set to be higher than the contact resistance between the main compound semiconductor layer 40 and the residual substrate portion 1.

本実施形態においては、反射部１７ｂは金属反射部とされている（以下、金属反射部１７ｂともいう）。そして、光取出側電極９の直下領域ＳＡにおいて該金属反射部１７ｂが、開口部１ｊの底面をなす化合物半導体部（ここでは、発光層部２４のｎ型クラッド層４）に対し、接合合金化層２１を介することなく、直接接して配置されている。光取出側電極９の直下領域ＳＡから接合合金化層２１を排除することで、主化合物半導体層４０と反射部１７ｂとの接触抵抗が高められている。図１において反射部１７ｂは、開口部１ｊ内に充填された金属ペースト層（以下、金属ペースト層１７ｂともいう）である。そして、残留基板部１の主裏面は、開口部１ｊ内を充填する金属ペースト層１７ｂの主裏面とともに放熱用金属部材１９（例えばＣｕ板ないしＡｌ板）により覆われている。金属ペースト層１７ｂは、放熱用金属部材１９を発光層部２４（主化合物半導体層４０）に結合する結合層と、反射部とに兼用されるものであり、Ａｇ等の金属粉末を結合用の樹脂及び溶剤からなるビヒクル中に分散させた金属ペーストを塗付後、乾燥させることにより形成されるものである。 In the present embodiment, the reflection portion 17b is a metal reflection portion (hereinafter also referred to as a metal reflection portion 17b). In the region SA immediately below the light extraction side electrode 9, the metal reflecting portion 17b is bonded to the compound semiconductor portion (here, the n-type cladding layer 4 of the light emitting layer portion 24) forming the bottom surface of the opening 1j. They are arranged in direct contact without interposing the layer 21. By eliminating the bonding alloying layer 21 from the region SA directly under the light extraction side electrode 9, the contact resistance between the main compound semiconductor layer 40 and the reflecting portion 17b is increased. In FIG. 1, the reflecting portion 17b is a metal paste layer (hereinafter also referred to as a metal paste layer 17b) filled in the opening 1j. The main back surface of the residual substrate portion 1 is covered with a heat radiating metal member 19 (for example, a Cu plate or an Al plate) together with the main back surface of the metal paste layer 17b filling the opening 1j. The metal paste layer 17b is used both as a bonding layer for bonding the heat-dissipating metal member 19 to the light-emitting layer portion 24 (main compound semiconductor layer 40) and a reflecting portion. It is formed by applying a metal paste dispersed in a vehicle composed of a resin and a solvent and then drying it.

金属ペースト層１７ｂの外周縁部には、これと一体化される形で、残留基板部１の主裏面を覆う導通経路ペースト層（金属ペーストからなる）１７ａが形成されている。そして、残留基板部１の主裏面には、導通経路ペースト層１７ａとの接触抵抗を減ずる接合合金化層１６が形成されている。接合合金化層１６は、Ａｕ又はＡｇを主成分として（５０質量％以上）、これに、接触先となる半導体の種別及び導電型に応じ、オーミック接触を取るための合金成分を適量配合した金属を半導体表面上に膜形成した後、合金化熱処理（いわゆるシンター処理）を施すことにより形成されたものである。本実施形態では、ｎ型ＧａＡｓからなる残留基板部１上に、ＡｕＧｅＮｉ合金（例えばＧｅ：１５質量％、Ｎｉ：１０質量％、残部Ａｕ）を用いた接合合金化層１６が形成されている。 On the outer peripheral edge of the metal paste layer 17b, a conduction path paste layer (made of metal paste) 17a covering the main back surface of the residual substrate 1 is formed so as to be integrated therewith. On the main back surface of the residual substrate portion 1, a bonding alloying layer 16 is formed that reduces the contact resistance with the conduction path paste layer 17a. The bonding alloying layer 16 is a metal containing Au or Ag as a main component (50 mass% or more), and an appropriate amount of an alloy component for making ohmic contact according to the type and conductivity type of the semiconductor to be contacted. After forming a film on the semiconductor surface, an alloying heat treatment (so-called sinter treatment) is performed. In the present embodiment, a bonding alloyed layer 16 using an AuGeNi alloy (for example, Ge: 15 mass%, Ni: 10 mass%, remaining Au) is formed on the residual substrate portion 1 made of n-type GaAs.

また、本実施形態において開口部１ｊは、主光取出面ＥＡの直下領域との重なりＰＡ（以下、単に直下領域ＰＡという）を有しており、該開口部１ｊ内に金属反射部（金属ペースト層）１７ｂが、主光取出面ＥＡの直下領域ＰＡと重なる形で設けられている。前述のごとく、発光層部２４と光取出側電極９との間には電流拡散層２０が設けられており、主光取出面ＥＡは、該電流拡散層２０の主表面周縁に沿って光取出側電極９を取り囲む形態で形成されている。そして、発光層部２４への通電経路を構成する残留基板部１は、該発光層部２４を含む主化合物半導体層４０の主裏面の周縁に沿って枠状に形成され、当該枠状の残留基板部１の内側に開口部１ｊが形成されている。また、光取出側電極９の主化合物半導体層４０の主裏面への投影外形線ＫＬは、枠状の残留基板部１の内側に位置するように、光取出側電極９と開口部１ｊとの形成位置及び領域寸法が定められている。そして、開口部１ｊにおいて、該枠状の残留基板部１の内縁と光取出側電極９の投影外形線ＫＬとの間に位置する領域ＰＡが、金属反射部（金属ペースト層）１７ｂにて覆われている。なお、図５及び図６に示すように、開口部１ｊの内側には、枠状の残留基板部１をさらに補強するための、補助残留基板部１ｗを設けることができる。本実施形態では、補助残留基板部１ｗを、開口部１ｊを複数個に仕切る形で直線状に形成している。図５は、補助残留基板部１ｗを、残留基板部１の対辺間をつなぐ十字状に形成した例であり、図６は、同じく残留基板部１の対角間をつなぐＸ字状に形成した例である。 Further, in the present embodiment, the opening 1j has an overlap PA (hereinafter simply referred to as a direct area PA) with a region directly below the main light extraction surface EA, and a metal reflecting portion (metal paste) is formed in the opening 1j. Layer) 17b is provided so as to overlap the area PA directly below the main light extraction surface EA. As described above, the current diffusion layer 20 is provided between the light emitting layer portion 24 and the light extraction side electrode 9, and the main light extraction surface EA extends along the periphery of the main surface of the current diffusion layer 20. It is formed in a form surrounding the side electrode 9. The residual substrate portion 1 constituting the energization path to the light emitting layer portion 24 is formed in a frame shape along the periphery of the main back surface of the main compound semiconductor layer 40 including the light emitting layer portion 24, and the frame-like residual An opening 1j is formed inside the substrate part 1. Further, the projected outline KL on the main back surface of the main compound semiconductor layer 40 of the light extraction side electrode 9 is positioned between the light extraction side electrode 9 and the opening 1j so as to be located inside the frame-like residual substrate portion 1. A formation position and a region size are determined. Then, in the opening 1j, a region PA located between the inner edge of the frame-like residual substrate portion 1 and the projected outline KL of the light extraction side electrode 9 is covered with a metal reflecting portion (metal paste layer) 17b. It has been broken. As shown in FIGS. 5 and 6, an auxiliary residual substrate portion 1w for further reinforcing the frame-like residual substrate portion 1 can be provided inside the opening 1j. In the present embodiment, the auxiliary residual substrate portion 1w is formed in a straight line so as to partition the opening 1j into a plurality of portions. FIG. 5 is an example in which the auxiliary residual substrate portion 1w is formed in a cross shape that connects the opposite sides of the residual substrate portion 1, and FIG. 6 is an example in which the auxiliary residual substrate portion 1w is formed in an X shape that similarly connects the diagonal portions of the residual substrate portion 1. It is.

開口部１ｊ内においては、接合合金化層を完全に排除する構成としてもよいし、主光取出面ＥＡの直下領域ＰＡには接合合金化層２１を分散形成するようにしてもよい（接合合金化層１６と材質は同じである）。この場合、金属反射部１７ｂは、開口部１ｊの底面をなす主化合物半導体部４０に対し、主光取出面ＥＡの直下領域ＰＡにおいては接合合金化層２１を介して接することになり、主光取出面ＥＡの直下領域ＰＡにおいて発光層部２４を、金属反射部１７ｂを介して通電発光させることができる。他方、残留基板部１の主裏面に形成される接合合金化層１６は、光反射にあまり寄与しないため、導通経路ペースト層１７ａとの接触抵抗低減を優先して、残留基板部１の主裏面の全面を覆うように形成される。他方、開口部１ｊ内における主光取出面ＥＡの直下領域ＰＡに接合合金化層２１を形成する場合は、接合合金化層２１の反射率が比較的低いため、該領域での反射光束を増加させる効果と、接合合金化層２１との接触抵抗を低減する効果とのバランスを考慮し、領域ＰＡの全面積に対する接合合金化層２１の形成面積の比率を１％以上２５％以下に調整することが望ましい。 In the opening 1j, the bonding alloyed layer may be completely eliminated, or the bonding alloyed layer 21 may be dispersedly formed in the region PA directly below the main light extraction surface EA (the bonding alloy). The material is the same as that of the chemical layer 16.) In this case, the metal reflecting portion 17b comes into contact with the main compound semiconductor portion 40 forming the bottom surface of the opening 1j via the bonding alloying layer 21 in the region PA directly below the main light extraction surface EA. In the region PA directly below the extraction surface EA, the light emitting layer portion 24 can be energized to emit light through the metal reflecting portion 17b. On the other hand, since the bonding alloying layer 16 formed on the main back surface of the residual substrate portion 1 does not contribute much to light reflection, priority is given to reducing the contact resistance with the conduction path paste layer 17a, so that the main back surface of the residual substrate portion 1 is given. It is formed so as to cover the entire surface. On the other hand, when the bonding alloyed layer 21 is formed in the area PA immediately below the main light extraction surface EA in the opening 1j, the reflectance of the bonding alloyed layer 21 is relatively low, so that the reflected light flux in the area increases. The ratio of the formation area of the bonding alloying layer 21 to the total area of the region PA is adjusted to 1% or more and 25% or less in consideration of the balance between the effect of reducing the contact resistance with the bonding alloying layer 21. It is desirable.

以下、図１の発光素子１００の製造方法について説明する。
まず、図２の工程１に示すように、ｎ型ＧａＡｓ単結晶からなる基板本体部１０ｍの主表面にＧａＡｓからなる図示しないバッファ層をエピタキシャル成長し、次に分離用化合物半導体層としてのエッチストップ層１０ｋ（例えばＡｌＩｎＰよりなる）をエピタキシャル成長し、さらに該エッチストップ層１０ｋ上に、ｎ型ＧａＡｓ単結晶からなる副基板部１０ｅをエピタキシャル成長して、発光層部２４を成長するための複合成長用基板１０を得る。副基板部１０ｅはＭＯＶＰＥ法又はＨＶＰＥ法により成長する。そして、工程２に示すように、その複合成長用基板１０の副基板部１０ｅの主表面に接して、バッファ層を形成することなく、発光層部２４として、ｎ型ＡｌＧａＩｎＰクラッド層４、ＡｌＧａＩｎＰ活性層（ノンドープ）５、及びｐ型ＡｌＧａＩｎＰクラッド層６を、この順序にて周知のＭＯＶＰＥ法により、エピタキシャル成長させる。続いて工程３に進み、電流拡散層２０（厚さ：１０μｍ以上２００μｍ以下（例えば１００μｍ））を、例えばハイドライド気相成長法あるいはＭＯＶＰＥ法を用いてエピタキシャル成長する。特に、ＧａＰないしＧａＡｓＰからなる電流拡散層２０は、ＨＶＰＥ法により良質のものを高速成長しやすい利点がある。 Hereinafter, a method for manufacturing the light emitting device 100 of FIG. 1 will be described.
First, as shown in step 1 of FIG. 2, a buffer layer (not shown) made of GaAs is epitaxially grown on the main surface of the substrate body 10m made of n-type GaAs single crystal, and then an etch stop layer as a compound semiconductor layer for separation. 10 k (for example, made of AlInP) is epitaxially grown, and the sub-substrate portion 10 e made of n-type GaAs single crystal is epitaxially grown on the etch stop layer 10 k to grow the light emitting layer portion 24. Get. The sub-substrate part 10e is grown by the MOVPE method or the HVPE method. Then, as shown in step 2, the n-type AlGaInP cladding layer 4 and the AlGaInP active layer are formed as the light-emitting layer portion 24 in contact with the main surface of the sub-substrate portion 10e of the composite growth substrate 10 without forming a buffer layer. The layer (non-doped) 5 and the p-type AlGaInP cladding layer 6 are epitaxially grown in this order by a well-known MOVPE method. Subsequently, the process proceeds to step 3, and the current diffusion layer 20 (thickness: 10 μm or more and 200 μm or less (for example, 100 μm)) is epitaxially grown using, for example, a hydride vapor phase growth method or a MOVPE method. In particular, the current diffusion layer 20 made of GaP or GaAsP has an advantage that a high-quality layer can be easily grown at a high speed by the HVPE method.

そして、工程４に進み、複合成長用基板１０から副基板部１０ｅを分離して、主化合物半導体層４０の主裏面上への残留基板部１となす処理を行なう。本実施形態では該処理を、ＧａＡｓに対して選択エッチング性を有する第一エッチング液（例えばアンモニア／過酸化水素混合液）を用いて基板本体部１０ｍをエッチング除去することにより行なう。その後、図３の工程５に進み、ＡｌＩｎＰに対して選択エッチング性を有する第二エッチング液（例えば塩酸：Ａｌ酸化層除去用にフッ酸を添加してもよい）を用いてＡｌＩｎＰエッチストップ層１０ｋをエッチング除去する。なお、分離用化合物半導体層として、エッチストップ層１０ｋに代えてＡｌＡｓ等からなる剥離層１０ｋを形成し、例えば１０％フッ酸水溶液からなるエッチング液に浸漬して該剥離層１０ｋを選択エッチングすることにより、複合成長用基板１０から副基板部１０ｅを分離して残留基板部１となす工程を採用してもよい。 Then, the process proceeds to step 4, where the sub-substrate portion 10 e is separated from the composite growth substrate 10, and the remaining substrate portion 1 on the main back surface of the main compound semiconductor layer 40 is processed. In the present embodiment, this processing is performed by etching away the substrate body 10m using a first etching solution (for example, ammonia / hydrogen peroxide mixed solution) having selective etching properties with respect to GaAs. Thereafter, the process proceeds to step 5 in FIG. 3, and the AlInP etch stop layer 10k is used by using a second etching solution (for example, hydrochloric acid: hydrofluoric acid may be added for removing the Al oxide layer) that has selective etching properties with respect to AlInP. Is removed by etching. As the separating compound semiconductor layer, a peeling layer 10k made of AlAs or the like is formed instead of the etch stop layer 10k, and the peeling layer 10k is selectively etched by dipping in an etching solution made of, for example, a 10% hydrofluoric acid aqueous solution. Thus, a process of separating the sub-substrate portion 10e from the composite growth substrate 10 to form the residual substrate portion 1 may be employed.

工程６に進み、残留基板部１上の周縁に沿って枠状に、ＡｕＧｅＮｉ合金からなる接触金属層１６’を形成する。また、電流拡散層２０の主表面には、光取出側電極９を形成する。接触金属層１６’は、開口部１ｊを形成するためのエッチングマスクの役割を兼用しており、蒸着あるいはスパッタリングにより周知のフォトリソグラフィー技術を用いて形成される。ただし、接触金属層１６’の表面を、感光性樹脂からなるエッチングレジスト層にて覆うようにしてもよい。次いで、工程７に示すように、ＧａＡｓからなる残留基板部１の該接触金属層１６’の内側に露出する部分をエッチングすることにより開口部１ｊを形成する。該開口部１ｊの形成により、残留基板部１は枠状となり、発光層部２４は露出面１８を開口部１ｊ内に形成する。そして、３５０℃以上５００℃以下の温度域で合金化熱処理を行なうことにより、接触金属層１６’を残留基板部１と合金化して接触合金化層１６とし、発光素子チップ３０ｃが得られる。 Proceeding to step 6, a contact metal layer 16 ′ made of an AuGeNi alloy is formed in a frame shape along the peripheral edge on the residual substrate portion 1. The light extraction side electrode 9 is formed on the main surface of the current diffusion layer 20. The contact metal layer 16 ′ also serves as an etching mask for forming the opening 1j, and is formed by vapor deposition or sputtering using a well-known photolithography technique. However, the surface of the contact metal layer 16 ′ may be covered with an etching resist layer made of a photosensitive resin. Next, as shown in Step 7, an opening 1j is formed by etching a portion of the residual substrate portion 1 made of GaAs exposed inside the contact metal layer 16 ′. By forming the opening 1j, the residual substrate portion 1 has a frame shape, and the light emitting layer portion 24 forms the exposed surface 18 in the opening 1j. Then, by performing an alloying heat treatment in a temperature range of 350 ° C. or higher and 500 ° C. or lower, the contact metal layer 16 ′ is alloyed with the residual substrate portion 1 to form the contact alloyed layer 16, and the light emitting element chip 30c is obtained.

ここで、開口部１ｊの内側（工程７で生ずる露出面１８）において、光取出側電極９の直下領域ＳＡには接合合金化層２１を形成しない（図１も参照）。また、枠状の残留基板部１の直上領域と、光取出側電極９の直下領域ＳＡとの間に挟まれた領域ＰＡには、図１に示すように、接合合金化層２１を例えば散点状に分散形成することができる。   Here, the bonding alloying layer 21 is not formed in the region SA immediately below the light extraction side electrode 9 inside the opening 1j (exposed surface 18 generated in step 7) (see also FIG. 1). Further, in the region PA sandwiched between the region directly above the frame-like residual substrate portion 1 and the region SA directly below the light extraction side electrode 9, as shown in FIG. It can be dispersedly formed in the form of dots.

図２の複合成長用基板１０上には、上記開口部１ｊを有する発光素子チップ３０ｃが、図４に示すように複数個マトリックス状に配列した形で一括形成される。このとき、残留基板部１は、隣接した発光素子チップ３０ｃ同士のものが一体化されているので、その幅方向中央位置に設定された切断線ＣＬに沿って切断することにより、個々の発光素子チップ３０ｃに分離される。そして、分離後の発光素子チップ３０ｃの主裏面側には、図１に示すように、開口部１ｊが充填され、かつ残留基板部１の主裏面が覆われるように金属ペーストが塗付され、金属ペースト層１７ｂと導通経路ペースト層１７ａとが一括形成される。そして、図３の工程８に示すように、それら金属ペースト層１７ｂと導通経路ペースト層１７ａとを介して放熱用金属部材１９を貼り合わせれば、図１の発光素子１００が得られる。 On the composite growth substrate 10 of FIG. 2, a plurality of light emitting element chips 30c having the openings 1j are collectively formed in a matrix array as shown in FIG. At this time, since the residual substrate portion 1 is formed by integrating the adjacent light emitting element chips 30c, the individual light emitting elements are cut by cutting along the cutting line CL set at the center position in the width direction. Separated into chips 30c. Then, a metal paste is applied to the main back surface side of the separated light emitting element chip 30c as shown in FIG. 1 so that the opening 1j is filled and the main back surface of the residual substrate portion 1 is covered, The metal paste layer 17b and the conduction path paste layer 17a are collectively formed. Then, as shown in Step 8 of FIG. 3, if the heat dissipating metal member 19 is bonded through the metal paste layer 17b and the conduction path paste layer 17a, the light emitting device 100 of FIG. 1 is obtained.

上記発光素子１００の複合成長用基板１０は、光吸収性化合物半導体であるＧａＡｓにて要部が構成されるが、これを発光層部２４の成長後に全て除去するのではなく副基板部１０ｅは残留基板部１として残すようにし、その一部を切り欠く形で開口部１ｊを形成し、その開口部１ｊ内を、反射部をなす金属ペースト層１７ｂにて充填する。そして、開口部１ｊの周縁に残された残留基板部１は、発光層部２４への剛性付与の機能を果たす。従って、特許文献１や非特許文献１のように、発光層部２４の主裏面側にはシリコン基板などの導電性基板を補強目的で新たに貼り合わせる必要がなくなる。 The substrate 10 for the composite growth of the light emitting device 100 is mainly composed of GaAs which is a light absorbing compound semiconductor. However, instead of removing all of this after the growth of the light emitting layer portion 24, the sub-substrate portion 10e An opening 1j is formed so as to leave as a residual substrate portion 1 and a part thereof is cut out, and the inside of the opening 1j is filled with a metal paste layer 17b forming a reflection portion. The residual substrate portion 1 left on the periphery of the opening 1j fulfills the function of imparting rigidity to the light emitting layer portion 24. Therefore, unlike Patent Document 1 and Non-Patent Document 1, it is not necessary to newly bond a conductive substrate such as a silicon substrate to the main back surface side of the light emitting layer portion 24 for the purpose of reinforcement.

また、本実施形態では、光取出側電極９を取り囲む形態で主光取出面ＥＡを形成し、残留基板部１を主光取出面ＥＡに対応した枠状に形成しているので、光取出側電極９を取り囲む主光取出面ＥＡの直下部分に電流を集中させることができ、発光層部２４を光取出しに有利な領域で優先的に発光させることができる。また、光取出側電極９と枠状の残留基板部１との間に形成される一定幅の領域ＰＡに金属ペースト層１７ｂを臨ませてあり、該領域ＰＡが存在するので反射光束ＲＢが光取出側電極９により遮られることが効果的に防止される。さらに、光取出側電極９の直下領域ＳＡからは、接合合金化層が排除されており、主化合物半導体層４０と反射部１７ｂとの接触抵抗が高められるので、発光光束が遮光されやすい光取出側電極９の直下領域ＳＡでの発光が抑制され、光取出し効率の更なる向上に寄与している。さらに、残留基板部１の主裏面は、金属ペースト層１７ｂを介して放熱用金属部材１９により覆われており、通電による発光層部２４の温度上昇が抑制される。 In the present embodiment, the main light extraction surface EA is formed in a form surrounding the light extraction side electrode 9, and the residual substrate portion 1 is formed in a frame shape corresponding to the main light extraction surface EA. The current can be concentrated at a portion directly below the main light extraction surface EA surrounding the electrode 9, and the light emitting layer portion 24 can be preferentially emitted in an area advantageous for light extraction. Further, the metal paste layer 17b is made to face a region PA having a constant width formed between the light extraction side electrode 9 and the frame-like residual substrate portion 1, and since the region PA exists, the reflected light beam RB is reflected by light. It is effectively prevented from being blocked by the extraction side electrode 9. Further, the bonding alloying layer is excluded from the region SA directly under the light extraction side electrode 9, and the contact resistance between the main compound semiconductor layer 40 and the reflecting portion 17b is increased, so that the light extraction light beam is easily blocked. Light emission in the region SA immediately below the side electrode 9 is suppressed, contributing to further improvement in light extraction efficiency. Furthermore, the main back surface of the residual substrate portion 1 is covered with the heat radiating metal member 19 via the metal paste layer 17b, and the temperature rise of the light emitting layer portion 24 due to energization is suppressed.

以下、第一態様の発光素子の変形例について説明する（図１の発光素子との共通部分には同一の符号を付与して詳細な説明は省略する）。まず、図９は、接合合金化層２１を光取出側電極９の該直下領域ＳＡにも配置した例である。光取出側電極９の直下での発光光束は、光取出側電極９にて一部遮られるが、直下領域ＳＡに存在する反射部（金属ペースト層１７ｂ）での斜め方向への反射光を大きくできる場合（例えば電流拡散層２０をある程度厚く形成した場合など）には、素子全体としての光取出し効率を向上できる場合がある。他方、図１０のように、開口部１ｊ内の領域に接合合金化層を全く形成しない構成も可能である。この場合は、残留基板部１の領域が主たる電流通路を構成するが、電流拡散層２０がある程度厚ければ、発光層部２４において残留基板部１の内側、つまり開口部１ｊの領域（特に、主光取出面ＥＡの直下領域ＰＡ）への回りこみ電流の発生も期待できる。接合合金化層の表面は反射率が多少低下するが、図１０のように、前記接合合金化層が主光取出面ＥＡの直下領域ＰＡから省略されていれば、該領域での反射効率をより高めることができ、素子全体としての光取出し効率を向上できる場合がある。   Hereinafter, modified examples of the light-emitting element of the first embodiment will be described (the same reference numerals are given to the common parts with the light-emitting element of FIG. 1 and detailed description will be omitted). First, FIG. 9 shows an example in which the bonding alloying layer 21 is also disposed in the region SA immediately below the light extraction side electrode 9. The emitted light beam directly under the light extraction side electrode 9 is partially blocked by the light extraction side electrode 9, but the reflected light in the oblique direction at the reflection portion (metal paste layer 17 b) existing in the region SA directly below is greatly increased. When possible (for example, when the current diffusion layer 20 is formed to be thick to some extent), the light extraction efficiency of the entire device may be improved. On the other hand, as shown in FIG. 10, a configuration in which no bonding alloying layer is formed in the region in the opening 1j is also possible. In this case, the region of the residual substrate portion 1 constitutes a main current path. However, if the current diffusion layer 20 is thick to some extent, the light emitting layer portion 24 is located inside the residual substrate portion 1, that is, the region of the opening 1j (particularly, Generation of a sneak current into the area PA immediately below the main light extraction surface EA can also be expected. Although the reflectance of the surface of the bonding alloyed layer is somewhat reduced, as shown in FIG. 10, if the bonding alloyed layer is omitted from the area PA directly below the main light extraction surface EA, the reflection efficiency in the area is increased. In some cases, the light extraction efficiency of the entire device can be improved.

次に、図７の発光素子２００においては、反射部が、開口部１ｊの底面をなす化合物半導体部上、ここでは発光層部２４（ｎ型クラッド層４）上に成膜された反射金属層３１（例えば、Ａｕ、ＡｇあるいはＡｌのいずれかを主成分とするものである）とされている。なお、残留基板部１の主裏面側は、接合合金化層１６を介して裏面電極３２にて覆われているが、これを反射金属層３１と同材質（例えばＡｕ）とすることで、裏面電極３２と反射金属層３１とを一括形成できる利点がある。一方、図８の発光素子３００のように、発光層部２４と残留基板部１との間に、屈折率の相違する半導体膜を複数積層することにより、ブラッグ反射を利用して光を反射させるＤＢＲ層３０が設けられている（ＤＢＲ層３０が設けられている以外は、図７と同じ構成である）。ＤＢＲ層３０は残留基板部１上にエピタキシャル成長可能である。なお、ＤＢＲ層３０は、図８では残留基板部１の領域にのみ選択的に形成されているが、開口部１ｊの底面領域にまでこれを延長して形成することもできる。 Next, in the light-emitting element 200 of FIG. 7, the reflective metal layer is formed on the compound semiconductor portion that forms the bottom surface of the opening 1j, in this case, on the light-emitting layer portion 24 (n-type cladding layer 4). 31 (for example, one containing Au, Ag, or Al as a main component). Note that the main back surface side of the residual substrate portion 1 is covered with the back electrode 32 via the bonding alloying layer 16, but by using the same material (for example, Au) as the reflective metal layer 31, There is an advantage that the electrode 32 and the reflective metal layer 31 can be formed together. On the other hand, a plurality of semiconductor films having different refractive indexes are stacked between the light emitting layer portion 24 and the residual substrate portion 1 as in the light emitting element 300 of FIG. 8 to reflect light using Bragg reflection. A DBR layer 30 is provided (the configuration is the same as in FIG. 7 except that the DBR layer 30 is provided). The DBR layer 30 can be epitaxially grown on the residual substrate portion 1. The DBR layer 30 is selectively formed only in the region of the remaining substrate portion 1 in FIG. 8, but can be formed to extend to the bottom region of the opening 1j.

（第二態様）
（実施形態Ａ）
図１１は、第二態様の一例である発光素子１１００を模式的に示すものである。なお、図１の発光素子１００との共通部分も多いので、以下、その相違点につき説明する。従って、以下に説明する相違点以外の部分は、図１の発光素子１００と同一の構成を有しているので、第一態様の説明にて代用するものとし、ここでは詳細な説明を繰り返さない。また、共通の構成要素には共通の符号を付与している。発光素子１１００は、発光層部２４を有した主化合物半導体層４０が副基板部１０ｅ（図１２参照）の主表面上にエピタキシャル成長されている。そして、主化合物半導体層４０の主表面側に主光取出面ＥＡが形成されるとともに、発光層部２４に発光駆動電圧を印加するための光取出側電極９が、主化合物半導体層４０の主表面の一部（具体的には、主光取出面ＥＡの残余領域）を覆うように形成されている。 (Second embodiment)
(Embodiment A)
Figure 11 shows a light emitting element 1100 is an example of a second embodiment schematically. In addition, since there are many common parts with the light emitting element 100 of FIG. 1, the difference will be described below. Therefore, since parts other than the differences described below have the same configuration as the light emitting element 100 of FIG. 1, the description of the first aspect is used instead, and the detailed description is not repeated here. . Moreover, the common code | symbol is provided to the common component. In the light emitting element 1100, the main compound semiconductor layer 40 having the light emitting layer portion 24 is epitaxially grown on the main surface of the sub-substrate portion 10e (see FIG. 12). Then, the main surface side of the main compound semiconductor layer 40 with main light extraction surface EA is formed, the light extraction side electrode 9 for applying emission drive voltage to the light emitting layer portion 24, the main of the main compound semiconductor layer 40 It is formed so as to cover a part of the surface (specifically, the remaining area of the main light extraction surface EA).

主化合物半導体層４０においては、発光層部２４の主表面上に、第一態様と同様の電流拡散層２０が形成され、該電流拡散層２０の主表面の略中央に前述の光取出側電極９（例えばＡｕ電極）が形成されている。他方、残留基板部１側においては、主光取出面ＥＡの直下部分に切欠き部１ｊが該残留基板部１を厚さ方向に貫通して形成され、主化合物半導体層４０の主裏面、ここでは補助電流拡散層９１の主裏面が切欠き部１ｊに露出している。残留基板部１は光取出側電極９の直下部分に形成され、本実施形態では、主化合物半導体層４０の該残留基板部１と接する部分（本実施形態ではｎ型クラッド層４）と同一導電型（すなわちｎ型）を有するものとされている。 In the main compound semiconductor layer 40, the current diffusion layer 20 similar to that of the first embodiment is formed on the main surface of the light emitting layer portion 24, and the above-described light extraction side electrode is formed at the approximate center of the main surface of the current diffusion layer 20. 9 (for example, an Au electrode) is formed. On the other hand, on the residual substrate portion 1 side, a notch 1j is formed in the portion immediately below the main light extraction surface EA so as to penetrate the residual substrate portion 1 in the thickness direction, and the main back surface of the main compound semiconductor layer 40, here Then, the main back surface of the auxiliary current diffusion layer 91 is exposed in the notch 1j. The residual substrate portion 1 is formed immediately below the light extraction side electrode 9, and in this embodiment, has the same conductivity as the portion of the main compound semiconductor layer 40 in contact with the residual substrate portion 1 (in this embodiment, the n-type cladding layer 4). It is assumed to have a type (ie, n-type).

本実施形態Ａにおいては、発光層部２４からの発光光束が、該切欠き部１ｊからも取り出し可能とされている。具体的には、残留基板部１の主裏面が、反射部材を兼ねた金属ステージ５２上に接着され、切欠き部１ｊから取り出された発光光束を該金属ステージ５２の反射面ＲＰにて反射させるようにしている。残留基板部１の主裏面には、その全面に裏面電極部をなす接合合金化層１６が形成されている。接合合金化層１６は、本実施形態ではＡｕＧｅＮｉ合金（例えばＧｅ：１５質量％、Ｎｉ：１０質量％、残部Ａｕ）を用いて形成されている。 In the present embodiment A, the luminous flux from the light emitting layer portion 24 can be taken out from the cutout portion 1j. Specifically, the main back surface of the residual substrate portion 1 is bonded onto the metal stage 52 that also serves as a reflecting member, and the emitted light beam taken out from the notch portion 1j is reflected by the reflecting surface RP of the metal stage 52. I am doing so. On the main back surface of the residual substrate portion 1, a bonding alloying layer 16 forming a back electrode portion is formed on the entire surface. In the present embodiment, the bonding alloying layer 16 is formed using an AuGeNi alloy (for example, Ge: 15% by mass, Ni: 10% by mass, balance Au).

この接合合金化層１６において残留基板部１は、金属ペースト層１１７を介して金属ステージ５２の反射面ＲＰ上に接着されている。これにより、発光層部２４は残留基板部１を導通路とする形で、金属ペースト層１１７を介して金属ステージ５２に電気的に接続される。一方、光取出側電極９は導体金具５１にＡｕワイヤ等で構成されたボンディングワイヤ９ｗを介して電気的に接続される。発光層部２４には、金属ステージ５２及び導体金具５１に一体化された図示しない駆動端子部を介して発光駆動電圧が印加される。金属ペースト層１１７は、第一態様と同様Ａｇペースト等により構成される。   In the bonded alloyed layer 16, the residual substrate portion 1 is bonded onto the reflective surface RP of the metal stage 52 via the metal paste layer 117. As a result, the light emitting layer portion 24 is electrically connected to the metal stage 52 through the metal paste layer 117 in the form of the remaining substrate portion 1 as a conduction path. On the other hand, the light extraction side electrode 9 is electrically connected to the conductor metal fitting 51 via a bonding wire 9w made of Au wire or the like. A light emission driving voltage is applied to the light emitting layer portion 24 via a drive terminal portion (not shown) integrated with the metal stage 52 and the conductor metal fitting 51. The metal paste layer 117 is composed of an Ag paste or the like as in the first embodiment.

また、残留基板部１と発光層部２４との間には、ＡｌＧａＩｎＰ、ＡｌＧａＡｓ、ＡｌＩｎＰ、ＧａＩｎＰ等の化合物半導体よりなる補助電流拡散層９１が形成されている。補助電流拡散層９１の厚さは例えば０．５μｍ以上３０μｍ以下（望ましくは１μｍ以上１５μｍ以下）であり、発光層部２４の、これに近い側のクラッド層（本実施形態ではｎ型クラッド層４）よりも有効キャリア濃度（従って、ｎ型ドーパント濃度）が高くされ、面内の電流拡散効果が高められている。なお、ｎ型クラッド層４（第一導電型クラッド層）の厚さをｐ型クラッド層６（第二導電型クラッド層）よりも厚くし、該ｎ型クラッド層４の主裏面側の表層部に補助電流拡散層としての機能を担わせることも可能である。 Further, an auxiliary current diffusion layer 91 made of a compound semiconductor such as AlGaInP, AlGaAs, AlInP, and GaInP is formed between the residual substrate portion 1 and the light emitting layer portion 24. The thickness of the auxiliary current diffusion layer 91 is, for example, not less than 0.5 μm and not more than 30 μm (preferably not less than 1 μm and not more than 15 μm). ), The effective carrier concentration (and hence the n-type dopant concentration) is increased, and the in-plane current diffusion effect is enhanced. The n-type cladding layer 4 (first conductivity type cladding layer) is made thicker than the p-type cladding layer 6 (second conductivity type cladding layer), and the surface layer portion on the main back surface side of the n-type cladding layer 4 It is also possible to have a function as an auxiliary current diffusion layer.

上記の構成によると、切欠き部１ｊの底面から取り出された発光光束を金属ステージ５２の反射面ＲＰにて反射させることで、その反射光束ＲＢにより発光層部２４の主表面側への発光光束を大幅に増加させることができる。残留基板部１と発光層部２４との間に設けられた補助電流拡散層９１は、切欠き部１ｊの底面部への電流拡散効果を高め、発光層部２４の該切欠き部１ｊに対応した領域への分配電流を増加させる。これにより、切欠き部１ｊの底面から取り出される発光光束をより増加することができる。 According to the above configuration, the emitted light beam extracted from the bottom surface of the notch 1j is reflected by the reflection surface RP of the metal stage 52, and the emitted light beam toward the main surface of the light emitting layer portion 24 by the reflected light beam RB Can be greatly increased. The auxiliary current diffusion layer 91 provided between the residual substrate portion 1 and the light emitting layer portion 24 enhances the current diffusion effect to the bottom surface portion of the notch portion 1j and corresponds to the notch portion 1j of the light emitting layer portion 24. Increase the distribution current to the area. Thereby, the emitted light beam taken out from the bottom surface of the notch 1j can be further increased.

以下、図１１の発光素子１１００の製造方法について説明する。
図１２の工程１〜工程４では、副基板部１０ｅの主表面に補助電流拡散層９１を成長し、続いて発光層部２４を成長させる点を除き、図２及び図３の工程１〜工程５と同じである。なお、電流拡散層２０は、ＧａＰ（あるいはＧａＡｓＰやＡｌＧａＡｓでもよい）からなる基板を発光層部２４に貼り合わせることにより形成してもよい。この場合は、発光層部２４に続く形でＡｌＩｎＰ、ＧａＩｎＰまたはＡｌＧａＡｓからなる結合層７を形成しておき、この結合層７にＧａＰないしＧａＡｓＰ、ＡｌＧａＡｓからなる基板を貼り合わせるようにすれば、該貼り合わせをより確実に行なうことができる。ＨＶＰＥ法を用いて電流拡散層２０をエピタキシャル成長する場合は、結合層７は特に不要である（この点、第一態様（図２、図３）においても同様である）。 Hereinafter, a method for manufacturing the light emitting element 1100 of FIG. 11 will be described.
In steps 1 to 4 of FIG. 12, steps 1 to steps of FIGS. 2 and 3 are performed except that the auxiliary current diffusion layer 91 is grown on the main surface of the sub-substrate portion 10e and the light emitting layer portion 24 is subsequently grown. Same as 5. The current diffusion layer 20 may be formed by bonding a substrate made of GaP (or GaAsP or AlGaAs) to the light emitting layer portion 24. In this case, if a coupling layer 7 made of AlInP, GaInP or AlGaAs is formed following the light emitting layer portion 24 and a substrate made of GaP, GaAsP, or AlGaAs is bonded to the coupling layer 7, Bonding can be performed more reliably. When the current spreading layer 20 is epitaxially grown by using the HVPE method, the coupling layer 7 is not particularly necessary (this also applies to the first mode (FIGS. 2 and 3)).

次に、工程５では、残留基板部１の主裏面の周縁部分を、周知のフォトリソグラフィー技術を用いてエッチングにより除去し、切欠き部１ｊを形成する。なお、エッチングの施された残留基板部１の主裏面にＡｕ等にて構成された電極部を形成することも可能であるが、この場合、残留基板部１の主裏面に該電極部を先に形成し、これを切欠き部１ｊを形成するためのエッチングマスクに兼用することもできる。そして、工程６に示すように、該残留基板部１の主裏面に、接合合金化層を形成するための金属材料層を蒸着等により形成し、３５０℃以上１５００℃以下の温度域で合金化熱処理を行なうことにより、接合合金化層１６とする。また、電流拡散層２０の主表面に接合合金化層９ａを同様に形成する（接合合金化層１６と合金化熱処理を兼用することができる）。接合合金化層９ａは図１１に示すごとく、Ａｕ等を蒸着することにより光取出側電極９にて覆う。その後、個々の発光素子チップに分離し、図１１に示すごとく、分離後の発光素子チップの残留基板部１の主裏面側を金属ペースト層１１７により金属ステージ５２に接着し、さらに光取出側電極９をボンディングワイヤ９ｗにより導体金具５１と接続すれば発光素子１１００が完成する。 Next, in step 5, the peripheral portion of the main back surface of the remaining substrate portion 1 is removed by etching using a well-known photolithography technique to form a notch portion 1j. It is possible to form an electrode portion made of Au or the like on the main back surface of the etched residual substrate portion 1. In this case, the electrode portion is first placed on the main back surface of the residual substrate portion 1. It can also be used as an etching mask for forming the notch 1j. Then, as shown in Step 6, a metal material layer for forming a bonding alloyed layer is formed on the main back surface of the residual substrate portion 1 by vapor deposition or the like, and alloyed in a temperature range of 350 ° C. to 1500 ° C. By performing heat treatment, the bonded alloyed layer 16 is obtained. Further, the bonding alloyed layer 9a is similarly formed on the main surface of the current spreading layer 20 (the bonding alloying layer 16 and the alloying heat treatment can be used together). As shown in FIG. 11, the bonding alloying layer 9a is covered with the light extraction side electrode 9 by vapor deposition of Au or the like. Thereafter, the light emitting device chips are separated into individual light emitting device chips. As shown in FIG. 11, the main back surface side of the remaining substrate portion 1 of the separated light emitting device chips is bonded to the metal stage 52 with the metal paste layer 117, and the light extraction side electrode is further bonded. 9 is connected to the conductor fitting 51 by the bonding wire 9w, the light emitting element 1100 is completed.

上記発光素子１１００の製造に用いられる複合成長用基板１０は、光吸収性化合物半導体であるＧａＡｓにて要部が構成されるが、これを発光層部２４の成長後に全て除去するのではなく、厚さを減じて残留基板部１とした後に、その一部切り欠く形で、光取出部として機能する切欠き部１ｊを形成する。そして、切欠き部１ｊ形成に関与しない部分は、発光層部２４への剛性付与の機能を果たす。従って、特許文献１や非特許文献１のように、発光層部２４の主裏面側にはシリコン基板などの導電性基板を補強目的で新たに貼り合わせる必要がなくなる。 The substrate 10 for compound growth used for manufacturing the light emitting device 1100 is mainly composed of GaAs which is a light absorbing compound semiconductor, but it is not completely removed after the light emitting layer portion 24 is grown. After the thickness is reduced to form the remaining substrate portion 1, a cutout portion 1 j that functions as a light extraction portion is formed in a partially cutout shape. And the part which does not participate in notch part 1j formation fulfill | performs the function of the rigidity provision to the light emitting layer part 24. FIG. Therefore, unlike Patent Document 1 and Non-Patent Document 1, it is not necessary to newly bond a conductive substrate such as a silicon substrate to the main back surface side of the light emitting layer portion 24 for the purpose of reinforcement.

図１１の実施形態では、残留基板部１の主裏面に接合合金化層１６を全面形成していたが、図１３に示すように、補助電流拡散層９１の主裏面（すなわち、切欠き部１ｊの底面）にて、残留基板部１の周囲に接合合金化層１６ｒを形成し、これを残留基板部１とともに金属ペースト層１１７により一括して覆う構成とすることもできる。このようにすると、残留基板部１と金属ペースト層１１７との接触抵抗が上昇し、光取出側電極９の直下に位置する残留基板部１の中央領域の電流密度を下げることができる。その結果、発光層部２４への駆動電流は、残留基板部１を迂回して主光取出面ＥＡ側に優先的に流れ、発光層部２４を光取出しに有利な領域で優先的に発光させることができる。なお、残留基板部１と接合合金化層１６ｒとをＡｕ層等の金属層で覆い、この金属層を介して金属ペースト層１１７により金属ステージ５２への接着を行なってもよい。 In the embodiment of FIG. 11, the bonding alloying layer 16 is formed on the main back surface of the residual substrate portion 1, but as shown in FIG. 13, the main back surface (that is, the notch portion 1 j) of the auxiliary current diffusion layer 91. It is also possible to form a bonding alloyed layer 16r around the residual substrate portion 1 at the bottom surface of the residual substrate portion 1 and to cover it with the metal paste layer 117 together with the residual substrate portion 1. If it does in this way, the contact resistance of the residual substrate part 1 and the metal paste layer 117 will rise, and the current density of the center area | region of the residual substrate part 1 located directly under the light extraction side electrode 9 can be lowered | hung. As a result, the drive current to the light emitting layer portion 24 bypasses the residual substrate portion 1 and flows preferentially to the main light extraction surface EA side, and causes the light emitting layer portion 24 to emit light preferentially in an area advantageous for light extraction. be able to. The residual substrate portion 1 and the bonded alloying layer 16r may be covered with a metal layer such as an Au layer, and the metal stage 52 may be bonded to the metal stage 52 through the metal layer.

（実施形態Ｂ）
図１４は、第二態様の別例である発光素子１２００を示す。なお、図１１の発光素子１１００（実施形態Ａ）との共通部分も多いので、以下、その相違点につき説明する。従って、以下に説明する相違点以外の部分は、図１１の発光素子１１００と同一の構成を有しているので、実施形態１の説明にて代用するものとし、ここでは詳細な説明を繰り返さない。また、共通の構成要素には共通の符号を付与している。 (Embodiment B)
Figure 14 shows a light emitting device 1200 is another example of the second embodiment. In addition, since there are many common parts with the light emitting element 1100 (embodiment A) of FIG. 11, the difference will be described below. Therefore, since parts other than the differences described below have the same configuration as that of the light emitting element 1100 of FIG. 11, they will be used in the description of Embodiment 1, and detailed description thereof will not be repeated here. . Moreover, the common code | symbol is provided to the common component.

発光素子１２００の、図１１の発光素子１１００との最も大きな相違点は、切欠き部１ｊの内部に、発光層部２４からの発光光束を反射させる金属反射部１７が設けられ、その反射光束ＲＢを、発光層部２４からの直接光束ＤＢと重畳させて主光取出面ＥＡから取り出すようにした点である。本実施形態においては、残留基板部１の主裏面が、切欠き部１ｊの底面とともに金属反射部１７に一括して覆われている。残留基板部１の形成領域における素子厚さ方向の電気抵抗は、切欠き部１ｊの形成領域における素子厚さ方向の電気抵抗よりも高く調整されてなる。具体的には、切欠き部１ｊの底面に、金属反射部１７との接触抵抗を減ずるための接合合金化層２１を分散形成する一方、残留基板部１の主裏面は接合合金化層を非形成としている。これにより、発光光束が遮光されやすい光取出側電極９の直下領域での発光が抑制されている。接合合金化層２１は、図１１の発光素子１１００の接合合金化層１６と同様に形成されるものであり、本実施形態では、ｎ型クラッド層４の主裏面上に、ＡｕＧｅＮｉ合金（例えばＧｅ：１５質量％、Ｎｉ：１０質量％、残部Ａｕ）を用いて形成されている。接合合金化層２１は反射率が比較的低いため、該領域での反射光束を増加させる効果と、接合合金化層２１との接触抵抗を低減する効果とのバランスを考慮し、領域ＥＡの全面積に対する接合合金化層２１の形成面積の比率を１％以上２５％以下に調整することが望ましい。 The biggest difference between the light emitting element 1200 and the light emitting element 1100 of FIG. 11 is that a metal reflecting portion 17 that reflects the luminous flux from the luminous layer portion 24 is provided inside the notch 1j, and the reflected luminous flux RB. Is extracted from the main light extraction surface EA while being superposed on the direct light beam DB from the light emitting layer portion 24. In the present embodiment, the main back surface of the residual substrate portion 1 is collectively covered with the metal reflecting portion 17 together with the bottom surface of the notch portion 1j. The electric resistance in the element thickness direction in the formation region of the residual substrate portion 1 is adjusted to be higher than the electric resistance in the element thickness direction in the formation region of the notch 1j. Specifically, the bonding alloyed layer 21 for reducing the contact resistance with the metal reflecting portion 17 is dispersedly formed on the bottom surface of the notch portion 1j, while the main back surface of the residual substrate portion 1 is not bonded to the bonding alloyed layer. It is supposed to form. As a result, light emission in the region immediately below the light extraction side electrode 9 where the luminous flux is easily shielded is suppressed. The bonding alloying layer 21 is formed in the same manner as the bonding alloying layer 16 of the light emitting element 1100 of FIG. 11. In this embodiment, an AuGeNi alloy (for example, Ge) is formed on the main back surface of the n-type cladding layer 4. : 15 mass%, Ni: 10 mass%, balance Au). Since the bonding alloyed layer 21 has a relatively low reflectance, considering the balance between the effect of increasing the reflected light flux in the region and the effect of reducing the contact resistance with the bonding alloyed layer 21, the entire region EA is considered. It is desirable to adjust the ratio of the formation area of the bonding alloying layer 21 to the area to 1% or more and 25% or less.

図１４において金属反射部１７は、切欠き部１ｊ内に充填された金属ペースト層（以下、金属ペースト層１７ともいう）である。そして、残留基板部１の主裏面は、切欠き部１ｊ内を充填する金属ペースト層１７の主裏面とともに放熱用金属部材１９（例えばＣｕ板ないしＡｌ板）により覆われている。金属ペースト層１７は、図１１の発光素子１１００と同様に形成されるものであり、具体的には、残留基板部１の主裏面と切欠き部１ｊの底面とを接着面として、該接着面に金属ペースト層１７を介して放熱用金属部材１９の主表面が接着されている。図１４では図示していないが、この放熱用金属部材１９が図１１と同様の金属ステージに接着される。また、光取出側電極９も図１１と同様、ボンディングワイヤを介して導体金具に接続される。なお、放熱用金属部材１９を省略し、残留基板部１の主裏面側を金属ステージに直接接着してもよい。 In FIG. 14, the metal reflecting portion 17 is a metal paste layer (hereinafter also referred to as a metal paste layer 17) filled in the notch portion 1j. The main back surface of the residual substrate portion 1 is covered with a heat radiating metal member 19 (for example, a Cu plate or an Al plate) together with the main back surface of the metal paste layer 17 filling the notch portion 1j. Metal paste layer 17, which is formed in the same manner as the light-emitting element 1100 in FIG. 11, specifically, the adhesive surface and a bottom surface of the main back surface and notches 1j of residual substrate portion 1, the adhesive surface The main surface of the heat radiating metal member 19 is bonded to the metal paste layer 17. Although not shown in FIG. 14, the heat radiating metal member 19 is bonded to the same metal stage as in FIG. The light extraction side electrode 9 is also connected to the conductor metal via a bonding wire as in FIG. The heat dissipating metal member 19 may be omitted, and the main back surface side of the residual substrate portion 1 may be directly bonded to the metal stage.

上記の切欠き部１ｊは、主光取出面ＥＡの直下領域と重なりを有する。本実施形態では、主光取出面ＥＡの直下領域が切欠き部１ｊの領域と略一致するように形成されているが、図１５に示すように、切欠き部１ｊを光取出側電極９の直下領域ＳＡに入り込む形で形成し、該切欠き部１ｊ内にて金属反射部１７を光取出側電極９の直下領域に入り込む形で形成することで、反射光束ＲＢのより効率的な取出しを図ることができる。他方、光吸収が過度に大きくならない範囲であれば、残留基板部１を主光取出面ＥＡの直下領域に多少入り込ませる構成も可能である。   The notch 1j has an overlap with a region directly below the main light extraction surface EA. In the present embodiment, the region immediately below the main light extraction surface EA is formed so as to substantially coincide with the region of the notch 1j, but the notch 1j is formed on the light extraction side electrode 9 as shown in FIG. It is formed so as to enter the region SA immediately below, and the metal reflecting portion 17 is formed so as to enter the region immediately below the light extraction side electrode 9 in the notch 1j, thereby more efficiently extracting the reflected light beam RB. Can be planned. On the other hand, as long as light absorption does not become excessively large, a configuration in which the residual substrate portion 1 slightly enters the region immediately below the main light extraction surface EA is also possible.

以下、図１４の発光素子１２００の製造方法について説明する。
まず、図１６の工程１から工程４及び図１７の工程５までは、副基板部１０ｅ上に発光層部２４を、補助電流拡散層を介挿することなく直接成長する点を除いて、図１２の工程１から工程５までと同じである。次に、図１７の工程６に進み、切欠き部１ｊの底面に、接合合金化層を形成するための金属材料層を蒸着等により分散形成し、３５０℃以上１５００℃以下の温度域で合金化熱処理を行なうことにより、接合合金化層２１とする。なお、残留基板部１の主裏面には接合合金化層２１を形成しない。また、金属反射膜３１を形成する場合は、その後の工程７にて行なう。以降は、図３と同様に、個々の発光素子チップに分離され、分離後の発光素子チップの主裏面側には、切欠き部１ｊが充填され、かつ残留基板部１の主裏面が覆われるように金属ペースト層１７が塗付形成される。そして、工程８に示すように、該金属ペースト層１７を介して放熱用金属部材１９を接着すれば、図１４の発光素子１２００が得られる。 Hereinafter, a method for manufacturing the light emitting device 1200 of FIG. 14 will be described.
First, from step 1 in FIG. 16 to step 4 and step 5 in FIG. 17, except that the light emitting layer portion 24 is directly grown on the sub-substrate portion 10 e without interposing the auxiliary current diffusion layer. This is the same as 12 steps 1 to 5. Next, the process proceeds to step 6 in FIG. 17, and a metal material layer for forming a bonded alloying layer is formed on the bottom surface of the notch 1j by vapor deposition or the like, and the alloy is formed in a temperature range of 350 ° C. to 1500 ° C. The bonded alloying layer 21 is formed by performing a heat treatment. Note that the bonding alloying layer 21 is not formed on the main back surface of the residual substrate portion 1. Further, when the metal reflective film 31 is formed, it is performed in the subsequent step 7. Thereafter, as in FIG. 3, the light emitting device chips are separated into individual light emitting device chips, and the main back surface side of the separated light emitting device chips is filled with the notch portion 1 j and the main back surface of the remaining substrate portion 1 is covered. Thus, the metal paste layer 17 is applied and formed. Then, as shown in Step 8, if the heat dissipating metal member 19 is bonded via the metal paste layer 17, the light emitting device 1200 of FIG. 14 is obtained.

切欠き部を有さない従来型の発光素子の場合、図１８に示すように、この接着により金属ペースト層１７がつぶれ変形して主化合物半導体層の周側面側に這い上がり、発光層部２４のｐ−ｎ接合部（本実施形態では、活性層５を挟んだｎ型クラッド層４とｐ型クラッド層６とを有するダブルへテロ構造）が這い上がった金属ペースト１７ｃにより短絡するなどの不具合を生じやすい。しかし、上記のごとく切欠き部１ｊが形成されていると、図１９に示すように、切欠き部１ｊを這い上がろうとする金属ペースト１７の吸収空間として利用でき、ｐ−ｎ接合部の短絡防止を図ることができる。また、ここでも、残留基板部１の主裏面を支持体表面に密着させ、切欠き部１ｊ内に充填された金属ペースト層により接着を行なうことで、残留基板部１の厚さ制御により金属ペースト層１７の厚さを一様に揃えることができる。この効果は第一態様においても同様に発揮される。 In the case of a conventional light emitting device having no cut-out portion, as shown in FIG. 18, the metal paste layer 17 is crushed and deformed by this adhesion and crawls up to the peripheral side surface of the main compound semiconductor layer. The pn junction portion (in this embodiment, a double hetero structure having the n-type cladding layer 4 and the p-type cladding layer 6 sandwiching the active layer 5) is short-circuited by the metal paste 17c that has been rolled up. It is easy to produce. However, when the notch 1j is formed as described above, as shown in FIG. 19, the notch 1j can be used as an absorption space for the metal paste 17 to scoop up and short-circuit the pn junction. Prevention can be achieved. Also in this case, the main back surface of the residual substrate portion 1 is brought into close contact with the support surface, and the metal paste layer is bonded by the metal paste layer filled in the notch portion 1j, whereby the metal paste is controlled by controlling the thickness of the residual substrate portion 1. The thickness of the layer 17 can be made uniform. This effect is also exhibited in the first embodiment.

なお、図では残留基板部１の厚さを電流拡散層２０よりも薄く描いているが、これは説明の便宜を図るためであって、残留基板部１と電流拡散層２０の厚さの大小関係を限定するものではない。特に、上記の金属ペースト１７の這い上がりによる不具合を解消するためには、残留基板部１の厚さを４０μｍ以上確保することが有効である（この場合、図１６の工程４に示す基板厚さを減少させる工程は不要となる場合がある）。なお、放熱用金属部材１９を用いる場合、放熱用金属部材用の大判の金属板に分離前のウェーハを金属ペースト１７を用いて接着し、その後ウェーハを金属板とともに素子チップへ分離することもできるが、この場合は個々の素子チップへの金属ペースト１７の這い上がりはほとんど問題とならない。従って、残留基板部１の厚さを４０μｍ未満に設定することも十分に可能である。   In the drawing, the thickness of the residual substrate portion 1 is drawn thinner than that of the current diffusion layer 20, but this is for convenience of explanation, and the thicknesses of the residual substrate portion 1 and the current diffusion layer 20 are large or small. It does not limit the relationship. In particular, it is effective to secure a thickness of the remaining substrate portion 1 of 40 μm or more in order to eliminate the problem caused by the creeping of the metal paste 17 (in this case, the substrate thickness shown in step 4 of FIG. 16). May be unnecessary.) When the heat radiating metal member 19 is used, the wafer before separation can be bonded to a large metal plate for the heat radiating metal member by using the metal paste 17, and then the wafer can be separated into the element chips together with the metal plate. In this case, however, the creeping of the metal paste 17 on each element chip hardly causes a problem. Therefore, it is possible to set the thickness of the remaining substrate portion 1 to less than 40 μm.

上記発光素子１２００は、残留基板部１に切欠き部１ｊを形成し、その切欠き部１ｊ内を、金属反射部をなす金属ペースト層１７にて充填する。本実施形態では、残留基板部１の主裏面に接合合金化層を形成していないので、光取出側電極９を取り囲む主光取出面ＥＡに電流を集中させることができ、発光層部２４を光取出しに有利な領域で優先的に発光させることができる。そして、この領域には金属反射部１７が配置されており、反射光束ＲＢにより光取出し効率が向上する。さらに、発光層部２４の主裏面側には、金属ペースト層１７を介して放熱用金属部材１９により覆われており、通電による発光層部２４の温度上昇が抑制される。 In the light emitting device 1200, a notch 1j is formed in the residual substrate portion 1, and the notch 1j is filled with a metal paste layer 17 that forms a metal reflecting portion. In the present embodiment, since no bonding alloyed layer is formed on the main back surface of the residual substrate portion 1, current can be concentrated on the main light extraction surface EA surrounding the light extraction side electrode 9, and the light emitting layer portion 24 is formed. Light can be preferentially emitted in an area advantageous for light extraction. In this region, the metal reflecting portion 17 is disposed, and the light extraction efficiency is improved by the reflected light beam RB. Furthermore, the main back surface side of the light emitting layer portion 24 is covered with the heat radiating metal member 19 via the metal paste layer 17, and the temperature rise of the light emitting layer portion 24 due to energization is suppressed.

以下、図１４の発光素子１２００のさらに別の実施形態について説明する（図１４の発光素子との共通部分には同一の符号を付与して詳細な説明は省略する）。 図１４の発光素子１２００の構成では、残留基板部１の主裏面に接合合金化層を形成しないことで、残留基板部１の領域における素子の厚さ方向抵抗を、切欠き部１ｊの領域における素子の厚さ方向抵抗よりも高くし、光吸収性の残留基板部１の直上部を電流迂回させるようにしている。しかし、同様の効果は、以下のような別の構成によっても達成することができる。まず、図２０の発光素子１３００においては、残留基板部１が、発光層部２４にてｐ−ｎ接合を形成するｐ型層部とｎ型層部とのうち、該残留基板部１に近い側のもの（すなわち、ｎ型クラッド層４）と逆の導電型（つまり、ｐ型）を有する反転層部１ｒとして構成している。この場合、副基板部としてｐ型のＧａＡｓエピタキシャル層を用いればよい。また、図２１の発光素子１４００においては、図１４の発光素子１２００と同様に残留基板部１を、発光層部２４にてｐ−ｎ接合を形成するｐ型層部とｎ型層部とのうち、該残留基板部に近い側のもの（すなわち、ｎ型クラッド層４）、と同一の導電型（つまりｎ型）を有するものとしている。そして、発光層部２４と残留基板部１との間には、残留基板部１を選択被覆する形で、該残留基板部１と逆の導電型（つまりｐ型）を有する化合物半導体からなる反転層部９３を介挿している。 Hereinafter, still another embodiment of the light-emitting element 1200 of FIG. 14 will be described (the same reference numerals are given to common portions with the light-emitting element of FIG. 14 and detailed description will be omitted). In the configuration of the light emitting device 1200 of FIG. 14, the bonding alloying layer is not formed on the main back surface of the residual substrate portion 1, so that the resistance in the thickness direction of the device in the region of the residual substrate portion 1 is reduced in the region of the notch portion 1j. It is higher than the resistance in the thickness direction of the element, and the current is directly bypassed immediately above the light-absorbing residual substrate portion 1. However, the same effect can be achieved by another configuration as described below. First, in the light emitting element 1300 of FIG. 20, the residual substrate portion 1 is close to the residual substrate portion 1 among the p-type layer portion and the n-type layer portion that form a pn junction in the light emitting layer portion 24. This is configured as an inversion layer portion 1r having a conductivity type (that is, p-type) opposite to that on the side (that is, n-type cladding layer 4). In this case, a p-type GaAs epitaxial layer may be used as the sub-substrate portion. Further, in the light emitting element 1400 of FIG. 21, the residual substrate portion 1 is formed of a p-type layer portion and an n-type layer portion that form a pn junction in the light emitting layer portion 24 as in the light emitting element 1200 of FIG. 14. Of these, the one close to the residual substrate portion (ie, n-type cladding layer 4) and the same conductivity type (ie, n-type) are used. An inversion made of a compound semiconductor having a conductivity type opposite to that of the residual substrate portion 1 (that is, p-type) is provided between the light emitting layer portion 24 and the residual substrate portion 1 so as to selectively cover the residual substrate portion 1. The layer part 93 is inserted.

次に、図２２の発光素子１５００においては、金属反射部が、切欠き部１ｊの底面をなす化合物半導体部上、ここでは発光層部２４（ｎ型クラッド層４）上に成膜された金属膜３１（例えば、Ａｕ、ＡｇあるいはＡｌのいずれかを主成分とするものである）とされている。なお、金属膜３１は、残留基板部１の主裏面側も一括して覆うものとされている。そして、該金属膜３１が金属ペースト層１７を介して放熱用金属部材１９に接合されている（この場合、金属ペースト層１７は金属反射部を構成するものではなくなる）。この金属膜３１は、図１７の工程７に示すように、接合合金化層２１の合金化熱処理後に形成される。 Next, in the light emitting element 1500 of FIG. 22, the metal reflecting portion is formed on the compound semiconductor portion that forms the bottom surface of the notch portion 1 j, in this case, on the light emitting layer portion 24 (n-type cladding layer 4). A film 31 (for example, one containing Au, Ag, or Al as a main component) is used. Note that the metal film 31 collectively covers the main back surface side of the residual substrate portion 1. The metal film 31 is bonded to the heat radiating metal member 19 via the metal paste layer 17 (in this case, the metal paste layer 17 does not constitute a metal reflecting portion). The metal film 31 is formed after the alloying heat treatment of the bonded alloying layer 21 as shown in Step 7 of FIG.

図２３の発光素子１６００は、図２２の発光素子１５００をさらに改良したもので、残留基板部１の主裏面の面積が主表面の面積よりも小となるように、該残留基板部１の周側面１ｓを傾斜面として形成している。そして、金属膜３１は、残留基板部１の主裏面及び周側面１ｓと、切欠き部１ｊの底面とを一体的に覆うものとされている。蒸着やスパッタ等の指向性の強い成膜法により金属膜３１を形成する場合、残留基板部１の周側面１ｓを上記のような傾斜面としておくことで、該周側面１ｓにも金属膜を十分な厚さにて形成することができる。 Emitting element 1600 in FIG. 23, a further modification of the light emitting element 1500 in FIG. 22, as the main back surface of the area of the residual substrate portion 1 is smaller than the area of the main surface, the remaining periphery of the substrate portion 1 The side surface 1s is formed as an inclined surface. The metal film 31 integrally covers the main back surface and the peripheral side surface 1s of the residual substrate portion 1 and the bottom surface of the cutout portion 1j. When the metal film 31 is formed by a highly directional film forming method such as vapor deposition or sputtering, the peripheral side surface 1s of the residual substrate portion 1 is formed as an inclined surface as described above, so that the metal film is also formed on the peripheral side surface 1s. It can be formed with a sufficient thickness.

周側面１ｓが傾斜面となった残留基板部１は、図１７の工程５のエッチングを、次のように実施することで得られる。まず、図２４の工程１に示すように、ＧａＡｓからなる残留基板部１と発光層部２４との間には、ＡｌＩｎＰよりなるエッチストップ層１ｐを形成しておく。次に、工程２に示すように、残留基板部１の主裏面（面方位を（１００）とする）のうち、残す領域をエッチングレジストＭＳＫにより覆い、残余の部分を、アンモニア−過酸化水素水溶液をエッチング液としてメサエッチングする。残留基板部１の周側面は、上記エッチング液の異方性エッチング効果により傾斜面となる。そして、工程３に示すように、塩酸をエッチング液としてエッチストップ層１ｐを除去し、さらにエッチングレジストＭＳＫを除去すればよい。 The remaining substrate portion 1 having the peripheral side surface 1s as an inclined surface can be obtained by performing the etching in step 5 of FIG. 17 as follows. First, as shown in Step 1 of FIG. 24, an etch stop layer 1p made of AlInP is formed between the residual substrate portion 1 made of GaAs and the light emitting layer portion 24. Next, as shown in step 2, the remaining region of the main back surface (with the surface orientation (100)) of the residual substrate portion 1 is covered with an etching resist MSK, and the remaining portion is covered with an ammonia-hydrogen peroxide solution. Is mesa-etched as an etchant. The peripheral side surface of the residual substrate portion 1 becomes an inclined surface due to the anisotropic etching effect of the etching solution. Then, as shown in step 3, the etch stop layer 1p may be removed using hydrochloric acid as an etchant, and the etching resist MSK may be removed.

次に、図２５の発光素子１７００は、発光層部２４と残留基板部１との間に、屈折率の相違する半導体膜を複数積層することにより、ブラッグ反射を利用して光を反射させるＤＢＲ層３０が設けられている（ＤＢＲ層３０が設けられている以外は、図１５と同じ構成である）。ＤＢＲ層３０により、主光取出面ＥＡ直下に位置する発光層部２４のうち、光吸収性の残留基板部１直上に位置する領域であっても、反射光束ＲＢを効果的に発生させることができる。この場合、残留基板部１を主光取出面ＥＡの直下領域に多少入り込む構成であっても、ＤＢＲ層３０の形成により光吸収による発光光束の損失はほとんど生じない。なお、図１１の発光素子１１００においても、残留基板部１と発光層部２４との間（例えば、補助電流拡散層９１と残留基板部１との間である）にＤＢＲ層を同様に形成することが可能である。また、図１１及び図１５のいずれの構造を基本とする場合においても、上記のＤＢＲ層を、切欠き部１ｊの底面領域まで延長して形成することが可能であり、切欠き部１ｊの領域における発光光束の反射効果を高めることができる。   Next, the light emitting element 1700 of FIG. 25 is a DBR that reflects light using Bragg reflection by stacking a plurality of semiconductor films having different refractive indexes between the light emitting layer portion 24 and the residual substrate portion 1. A layer 30 is provided (the configuration is the same as in FIG. 15 except that the DBR layer 30 is provided). The DBR layer 30 can effectively generate the reflected light beam RB even in a region located immediately above the light-absorbing residual substrate portion 1 in the light emitting layer portion 24 located immediately below the main light extraction surface EA. it can. In this case, even if the residual substrate portion 1 is configured to enter the region immediately below the main light extraction surface EA, the loss of the luminous flux due to light absorption hardly occurs due to the formation of the DBR layer 30. In the light emitting element 1100 of FIG. 11 as well, a DBR layer is similarly formed between the residual substrate portion 1 and the light emitting layer portion 24 (for example, between the auxiliary current diffusion layer 91 and the residual substrate portion 1). It is possible. Further, in the case of using the structure of either FIG. 11 or FIG. 15 as a base, the above DBR layer can be formed to extend to the bottom surface region of the notch 1j, and the region of the notch 1j. It is possible to enhance the reflection effect of the emitted luminous flux.

（第三態様）
以下、第三態様の実施形態を添付の図面を用いて説明する。図２６は本発明の第三態様の一例である発光素子２１００を模式的に示すものである。なお、図１の発光素子１００との共通部分も多いので、以下、その相違点につき説明する。従って、以下に説明する相違点以外の部分は、図１の発光素子１００と同一の構成を有しているので、第一態様の説明にて代用するものとし、ここでは詳細な説明を繰り返さない。また、共通の構成要素には共通の符号を付与している。 (Third embodiment)
Hereinafter will be described with reference to the accompanying drawings embodiments of the third aspect. FIG. 26 schematically shows a light-emitting element 2100 that is an example of the third embodiment of the present invention. In addition, since there are many common parts with the light emitting element 100 of FIG. 1, the difference will be described below. Therefore, since parts other than the differences described below have the same configuration as the light emitting element 100 of FIG. 1, the description of the first aspect is used instead, and the detailed description is not repeated here. . Moreover, the common code | symbol is provided to the common component.

図２６は、第三態様の一例である発光素子２１００を模式的に示すものである。発光素子２１００において発光層部２４を有した主化合物半導体層４０は、副基板部１０ｅ（図２７の工程２参照）の主表面上にエピタキシャル成長されたものである。そして、該残留基板部１の周縁部が切り欠かれることにより切欠き部１ｊが形成される（図２７の工程５参照）。図２７の工程２は層成長時の上下関係で描いており、図２６はこれと上下反転している（従って、主表面は、図２６中にて層や基板の下面として表れる）。切欠き部１ｊの底面は主光取出面ＥＡを形成し、発光層部２４に発光駆動電圧を印加するための光取出側電極９が残留基板部１の主裏面を覆うように形成されている。図２６において、透明半導体層９０、結合層７、発光層部２４及び補助電流拡散層９１は主化合物半導体層４０に属し、残留基板部１は主化合物半導体層４０に属さない。 Figure 26 shows a light emitting element 2100 is an example of a third embodiment schematically. The main compound semiconductor layer 40 having the light emitting layer portion 24 in the light emitting element 2100 is epitaxially grown on the main surface of the sub-substrate portion 10e (see step 2 in FIG. 27). And the notch part 1j is formed by notching the peripheral part of this residual substrate part 1 (refer the process 5 of FIG. 27). Step 2 in FIG. 27 is drawn in a vertical relationship during layer growth, and FIG. 26 is inverted vertically (therefore, the main surface appears as the lower surface of the layer or substrate in FIG. 26). The bottom surface of the cutout portion 1j forms a main light extraction surface EA, and the light extraction side electrode 9 for applying a light emission driving voltage to the light emitting layer portion 24 is formed so as to cover the main back surface of the residual substrate portion 1. . In FIG. 26, the transparent semiconductor layer 90, the bonding layer 7, the light emitting layer portion 24, and the auxiliary current diffusion layer 91 belong to the main compound semiconductor layer 40, and the residual substrate portion 1 does not belong to the main compound semiconductor layer 40.

発光素子２１００においては、透明半導体層９０側にｐ型ＡｌＧａＩｎＰクラッド層６が配置されており、残留基板部１側にｎ型ＡｌＧａＩｎＰクラッド層４が配置されている。残留基板部１と光取出側電極９との間には、両者の接触抵抗を減ずるための接合合金化層９ａが形成されている。接合合金化層９ａは、ここではＡｕＧｅＮｉ合金（例えばＧｅ：１５質量％、Ｎｉ：１０質量％、残部Ａｕ）を用いて形成している。   In the light emitting element 2100, the p-type AlGaInP clad layer 6 is disposed on the transparent semiconductor layer 90 side, and the n-type AlGaInP clad layer 4 is disposed on the residual substrate portion 1 side. Between the residual substrate part 1 and the light extraction side electrode 9, a bonding alloyed layer 9a is formed for reducing the contact resistance between them. Here, the bonding alloyed layer 9a is formed using an AuGeNi alloy (for example, Ge: 15% by mass, Ni: 10% by mass, balance Au).

主化合物半導体層４０においては、発光層部２４の主表面上に、ＧａＰ（あるいはＧａＡｓＰやＡｌＧａＡｓでもよい：ここではｐ型）よりなる透明半導体層９０が形成されている。透明半導体層９０は接合合金化層２１によりオーミック接触が形成できる程度に有効キャリア濃度（従って、ｐ型ドーパント濃度）が高められている（例えばｐ型クラッド層６と同等以上であって２×１０１８／ｃｍ３以下）。透明半導体層９０は、例えば１０μｍ以上２００μｍ以下（好ましくは４０μｍ以上２００μｍ以下）の厚膜に形成されることで、層側面からの取出光束も増加させ、発光素子全体の輝度（積分球輝度）を高める役割も担う。また、発光層部２４からの発光光束のピーク波長に相当する光量子エネルギーよりも大きなバンドギャップエネルギーを有するＩＩＩ−Ｖ族化合物半導体にて構成することで、発光光束に対する吸収も抑制されている。 In the main compound semiconductor layer 40, on the main surface of the light emitting layer portion 24, GaP (or GaAsP or AlGaAs even better: here p-type) are formed transparent semiconductor layer 90 made of. The transparent semiconductor layer 90 has an effective carrier concentration (and therefore a p-type dopant concentration) increased to such an extent that an ohmic contact can be formed by the bonded alloying layer 21 (for example, equal to or higher than the p-type cladding layer 6 and 2 × 10 18 / cm 3 or less). The transparent semiconductor layer 90 is formed in a thick film of, for example, 10 μm or more and 200 μm or less (preferably 40 μm or more and 200 μm or less), thereby increasing the extracted light flux from the side surface of the layer and increasing the luminance (integrated sphere luminance) of the entire light emitting element. It also plays a role to raise. Moreover, absorption with respect to the emitted light beam is also suppressed by using a III-V group compound semiconductor having a band gap energy larger than the photon energy corresponding to the peak wavelength of the emitted light beam from the light emitting layer portion 24.

透明半導体層９０の主表面側は、金属ステージ５２上にＡｇペースト等からなる金属ペースト層１７を介して接着され、該金属ペースト層１７が反射部を形成している。また、透明半導体層９０の主表面には、光取出側電極９側と同様に接合合金化層２１が分散形成され、該接合合金化層２１が金属ペースト層１７により覆われている。これにより、発光層部２４は、金属ペースト層１７を介して金属ステージ５２に電気的に接続される。一方、光取出側電極９は、導体金具５１にＡｕワイヤ等で構成された通電用ワイヤ９ｗを介して電気的に接続される。発光層部２４には、金属ステージ５２及び導体金具５１に一体化された図示しない駆動端子部を介して発光駆動電圧が印加される。 The main surface side of the transparent semiconductor layer 90 is bonded to the metal stage 52 via the metal paste layer 17 made of Ag paste or the like, and the metal paste layer 17 forms a reflection portion. Further, a bonding alloyed layer 21 is formed on the main surface of the transparent semiconductor layer 90 in the same manner as the light extraction side electrode 9 side, and the bonding alloyed layer 21 is covered with the metal paste layer 17. As a result, the light emitting layer portion 24 is electrically connected to the metal stage 52 through the metal paste layer 17. On the other hand, the light extraction side electrode 9 is electrically connected to the conductor metal fitting 51 via a current-carrying wire 9w made of Au wire or the like. A light emission driving voltage is applied to the light emitting layer portion 24 via a drive terminal portion (not shown) integrated with the metal stage 52 and the conductor metal fitting 51.

本実施形態において接合合金化層２１は、ｐ型層とのコンタクトを取るためにＡｕＢｅ合金を用いて形成されている。接合合金化層２１は反射率が比較的低いため、該領域での反射光束を増加させる効果と、接合合金化層２１との接触抵抗を低減する効果とのバランスを考慮し、透明半導体層９０の主表面の全面積に対する接合合金化層２１の形成面積の比率を１％以上２５％以下に調整することが望ましい。なお、接合合金化層２１をＡｕ層、Ａｇ層あるいはＡｌ層などの高反射率の金属反射層３１で覆い、該金属反射層３１を、金属ペースト層１７を介して金属ステージ５２に接着してもよい。 In this embodiment, the bonding alloying layer 21 is formed using an AuBe alloy in order to make contact with the p-type layer. Since the bonding alloyed layer 21 has a relatively low reflectance, the transparent semiconductor layer 90 is considered in consideration of the balance between the effect of increasing the reflected light flux in the region and the effect of reducing the contact resistance with the bonding alloyed layer 21. It is desirable to adjust the ratio of the formation area of the bonding alloying layer 21 to the total area of the main surface of the steel to 1% or more and 25% or less. The bonded alloyed layer 21 is covered with a highly reflective metal reflective layer 31 such as an Au layer, an Ag layer, or an Al layer, and the metal reflective layer 31 is adhered to the metal stage 52 via the metal paste layer 17. Also good.

なお、透明半導体層９０の側で発光素子を、金属ペースト層１７を介して金属ステージ５２に接着する場合、図２６に一部拡大して示すように、その接着時に金属ペースト層１７がつぶれ変形して主化合物半導体層の周側面側に這い上がることがある。しかし、本実施形態では、この接着側に設ける透明半導体層９０の厚さを４０μｍ以上２００μｍ以下と厚くしてあり、仮に金属ペーストが這い上がっても発光層部（ｐ−ｎ接合部）２４にまで達する確率は小さくなり、ｐ−ｎ接合の短絡等を効果的に防止できる。   When the light emitting element is bonded to the metal stage 52 through the metal paste layer 17 on the transparent semiconductor layer 90 side, the metal paste layer 17 is crushed and deformed at the time of bonding as shown in FIG. In some cases, the main compound semiconductor layer may crawl up to the peripheral side surface. However, in the present embodiment, the thickness of the transparent semiconductor layer 90 provided on the bonding side is increased to 40 μm or more and 200 μm or less, and even if the metal paste crawls up, the light emitting layer portion (pn junction) 24 is formed. The probability of reaching up to is reduced, and a pn junction short circuit or the like can be effectively prevented.

また、残留基板部１と発光層部２４との間には、ＡｌＧａＩｎＰ、ＡｌＧａＡｓ、ＡｌＩｎＰ、ＧａＩｎＰ等の化合物半導体よりなる補助電流拡散層９１が形成されている。補助電流拡散層９１の厚さは例えば０．５μｍ以上３０μｍ以下（望ましくは１μｍ以上１５μｍ以下）であり、発光層部２４の、これに近い側のクラッド層（本実施形態ではｎ型クラッド層４）よりも有効キャリア濃度（従って、ｎ型ドーパント濃度）が高くされ、面内の電流拡散効果が高められている。なお、ｎ型クラッド層４（第一導電型クラッド層）の厚さをｐ型クラッド層６（第二導電型クラッド層）よりも厚くし、該ｎ型クラッド層４の主裏面側の表層部に補助電流拡散層としての機能を担わせることも可能である。 Further, an auxiliary current diffusion layer 91 made of a compound semiconductor such as AlGaInP, AlGaAs, AlInP, and GaInP is formed between the residual substrate portion 1 and the light emitting layer portion 24. The thickness of the auxiliary current diffusion layer 91 is, for example, not less than 0.5 μm and not more than 30 μm (preferably not less than 1 μm and not more than 15 μm). ), The effective carrier concentration (and hence the n-type dopant concentration) is increased, and the in-plane current diffusion effect is enhanced. The n-type cladding layer 4 (first conductivity type cladding layer) is made thicker than the p-type cladding layer 6 (second conductivity type cladding layer), and the surface layer portion on the main back surface side of the n-type cladding layer 4 It is also possible to have a function as an auxiliary current diffusion layer.

上記の構成によると、光吸収部として作用する残留基板部１の一部のみが切り欠かれている。これにより、形成される切欠き部１ｊの底面を主光取出面ＥＡとして利用することができ、該部分へ向かう発光光束を外部へ直接取り出すことが可能となるので、光取出し効率を大幅に高めることができる。他方、残留基板部１の主裏面は光取出側電極９の形成領域として活用され、光取出側電極９（図２６）による光遮断作用により、残留基板部１による光吸収作用が不具合として顕在化しなくなっている。また、バンドギャップエネルギーが小さく耐酸化性にも優れるＧａＡｓからなる残留基板部１の主裏面に光取出側電極９用の接合合金化層９ａを形成することで、より良好なオーミックコンタクトが実現し、素子の順方向電圧低減に寄与している。 According to said structure, only a part of residual substrate part 1 which acts as a light absorption part is notched. As a result, the bottom surface of the formed notch portion 1j can be used as the main light extraction surface EA, and the emitted light beam directed toward the portion can be directly extracted to the outside, so that the light extraction efficiency is greatly increased. be able to. On the other hand, the main back surface of the residual substrate portion 1 is used as formation region of the light extraction side electrode 9, the light shielding effect of the light extraction side electrode 9 (FIG. 26), the light absorption by the residual substrate portion 1 is manifested as bug It is gone. Further, a better ohmic contact can be realized by forming the bonding alloyed layer 9a for the light extraction side electrode 9 on the main back surface of the residual substrate portion 1 made of GaAs having a small band gap energy and excellent oxidation resistance. This contributes to reducing the forward voltage of the element.

以下、図２６の発光素子２１００の製造方法について説明する。
図２７の工程１〜工程５までは、電流拡散層２０を透明半導体層９０と読み替えれば、図１２の工程１〜工程５と全く同じである。工程６（工程５までと上下を反転して描いている）では、該残留基板部１の主裏面に、接合合金化層を形成するための金属材料層を蒸着等により形成し、３５０℃以上２５００℃以下の温度域で合金化熱処理を行なうことにより、接合合金化層９ａとする。また、透明半導体層９０の主表面に接合合金化層２１を同様に分散形成する（接合合金化層９ａと合金化熱処理を兼用することができる）。接合合金化層９ａは図２６に示すごとく、Ａｕ等を蒸着することにより光取出側電極９にて覆う。その後、図３と同様に個々の発光素子チップに分離され、図２６に示すごとく、分離後の発光素子チップの透明半導体層９０の主裏面（接合合金化層２１が形成されている）を金属ペースト層１７により金属ステージ５２に接着し、さらに光取出側電極９をボンディングワイヤ９ｗにより導体金具５１と接続すれば発光素子２１００が完成する。 Hereinafter, a method for manufacturing the light-emitting element 2100 of FIG. 26 will be described.
Steps 1 to 5 in FIG. 27 are exactly the same as steps 1 to 5 in FIG. 12 if the current diffusion layer 20 is read as the transparent semiconductor layer 90. In step 6 (drawn upside down with respect to step 5), a metal material layer for forming a bonding alloyed layer is formed on the main back surface of the residual substrate portion 1 by vapor deposition or the like, and 350 ° C. or higher. By performing an alloying heat treatment in a temperature range of 2500 ° C. or less, a bonded alloyed layer 9a is obtained. In addition, the bonding alloying layer 21 is similarly dispersedly formed on the main surface of the transparent semiconductor layer 90 (the bonding alloying layer 9a can also be used as an alloying heat treatment). As shown in FIG. 26, the bonding alloyed layer 9a is covered with the light extraction side electrode 9 by vapor deposition of Au or the like. Thereafter, as shown in FIG. 3, the light emitting device chips are separated into individual light emitting device chips. As shown in FIG. 26, the main back surface (the bonding alloyed layer 21 is formed) of the transparent semiconductor layer 90 of the light emitting device chips after separation is metalized. The light emitting element 2100 is completed by bonding the paste layer 17 to the metal stage 52 and connecting the light extraction side electrode 9 to the conductor fitting 51 by the bonding wire 9w.

上記発光素子２１００は、残留基板部１を一部切り欠く形で、主光取出面ＥＡとして機能する切欠き部１ｊを形成する。そして、切欠き部１ｊ形成に関与しない部分は、ウェーハの剛性向上機能も果たしうる。   The light emitting element 2100 forms a cutout portion 1j that functions as the main light extraction surface EA in a form in which the residual substrate portion 1 is partially cutout. And the part which does not participate in notch part 1j formation can also fulfill the rigidity improvement function of a wafer.

以下、第三態様の実施形態の発明の発光素子の種々の変形例について説明する。なお、図２６の発光素子２１００との共通部分も多いので、以下、その相違点につき説明する。従って、以下に説明する相違点以外の部分は、図２６の発光素子２１００と同一の構成を有しているので、ここでは詳細な説明を繰り返さない。また、共通の構成要素には共通の符号を付与する。   Hereinafter, various modified examples of the light emitting device of the embodiment of the third aspect will be described. Since there are many common parts with the light emitting element 2100 in FIG. 26, the differences will be described below. Accordingly, the portions other than the differences described below have the same configuration as that of the light emitting element 2100 in FIG. 26, and thus detailed description thereof will not be repeated here. Also, common reference numerals are assigned to common components.

図２８の発光素子２３００には、発光層部２４と残留基板部１との間に、屈折率の相違する半導体膜を複数積層することにより、ブラッグ反射を利用して光を反射させるＤＢＲ層３０が設けられている。ＤＢＲ層３０は、光吸収性の残留基板部１の直下に位置する領域であっても、発光光束ＥＢを下向きに反射することができるので、発光光束ＤＢが残留基板部１に吸収されて損失する不具合を解消することができる。反射された発光光束ＤＢは残留基板部等に吸収されない限り、直接あるいは素子の別部分（例えば金属ペースト層１７あるいは反射金属層３１）での反射を利用して素子外へ取り出すことが可能になる。   In the light emitting element 2300 of FIG. 28, a plurality of semiconductor films having different refractive indexes are stacked between the light emitting layer portion 24 and the residual substrate portion 1 to reflect light by using Bragg reflection. Is provided. Even if the DBR layer 30 is an area located directly below the light-absorbing residual substrate portion 1, it can reflect the emitted light beam EB downward, so that the emitted light beam DB is absorbed by the residual substrate portion 1 and lost. Can be solved. As long as the reflected luminous flux DB is not absorbed by the residual substrate portion or the like, it can be taken out of the element directly or by using reflection at another part of the element (for example, the metal paste layer 17 or the reflective metal layer 31). .

図２９の発光素子２４００では、補助電流拡散層９１の主裏面（すなわち、切欠き部１ｊの底面）にて、残留基板部１の周囲に接合合金化層９ａを形成し、これを残留基板部１とともに光取出側電極９により一括して覆う構成とすることもできる。この場合、光取出側電極９は、残留基板部１の主裏面及び周側面とを覆う主電極９ｍと、切欠き部１ｊの底面のうち残留基板部１の周側面に連なる一部領域を覆う副電極９ｂとを有したものとして形成される。接触抵抗低減用の接合合金化層９ａは、主電極９ｍと接する残留基板部１には形成されず、副電極９ｂと接する切欠き部１ｊの底面領域には形成されることとなる。従って、発光駆動電流は残留基板部１を迂回して主光取出面側に優先的に流れ、光取出し効率が向上する。 In the light emitting element 2400 of FIG. 29, the bonding alloyed layer 9a is formed around the residual substrate portion 1 on the main back surface of the auxiliary current diffusion layer 91 (that is, the bottom surface of the notch portion 1j), and this is formed on the residual substrate portion. 1 and the light extraction side electrode 9 together. In this case, the light extraction side electrode 9 covers a main electrode 9m that covers the main back surface and the peripheral side surface of the residual substrate portion 1, and a partial region that continues to the peripheral side surface of the residual substrate portion 1 among the bottom surface of the notch portion 1j. The auxiliary electrode 9b is formed. The bonding alloying layer 9a for reducing contact resistance is not formed on the remaining substrate portion 1 in contact with the main electrode 9m, but is formed in the bottom surface region of the notch portion 1j in contact with the sub electrode 9b. Therefore, the light emission drive current bypasses the residual substrate portion 1 and flows preferentially to the main light extraction surface side, and the light extraction efficiency is improved.

なお、透明半導体層９０あるいは副電極９ｂにより十分な電流拡散効果が得られる場合は、補助電流拡散層９１を省略することも可能である。この場合、切欠き部１ｊの底面は発光層部２４の主裏面が形成する。また、副電極９ｂを設ける場合は、接合合金化層９ａとともに発光層部２４上に形成することとなる。 Note that the auxiliary current diffusion layer 91 may be omitted when a sufficient current diffusion effect is obtained by the transparent semiconductor layer 90 or the sub-electrode 9b. In this case, the bottom surface of the notch portion 1j is formed by the main back surface of the light emitting layer portion 24. Moreover, when providing the subelectrode 9b, it will form on the light emitting layer part 24 with the joining alloying layer 9a.

また、残留基板部１の主裏面の面積が主表面の面積よりも小となるように、該残留基板部１の周側面１ｓが傾斜面として形成されている。光取出側電極９をなす主電極９ｍ（すなわち、残留基板部１の主裏面及び周側面１ｓとを覆う部分）と副電極９ｂ（切欠き部１ｊの底面を覆う部分）とは、一体の金属膜として形成される。このような形状の残留基板部１は、図２４と同様の工程により製造可能である。 Further, the peripheral side surface 1s of the residual substrate portion 1 is formed as an inclined surface so that the area of the main back surface of the residual substrate portion 1 is smaller than the area of the main surface . The main electrode 9m forming the light extraction side electrode 9 (that is, the portion covering the main back surface and the peripheral side surface 1s of the residual substrate portion 1) and the sub electrode 9b (the portion covering the bottom surface of the notch portion 1j) are an integral metal. Formed as a film. The residual substrate portion 1 having such a shape can be manufactured by the same process as in FIG.

図３０の発光素子２５００においては、図２９の発光素子２４００の残留基板部１を、発光層部２４にてｐ−ｎ接合を形成するｐ型層部とｎ型層部とのうち、該残留基板部１に近い側のもの（すなわち、ｎ型クラッド層４）と逆の導電型（つまり、ｐ型）を有する反転層部１ｒとして構成している。この場合、光吸収性化合物半導体基板としてｐ型の副基板部を用いればよい。また、図３１の発光素子２６００においては、図２９の発光素子２４００と同様に残留基板部１を、発光層部２４にてｐ−ｎ接合を形成するｐ型層部とｎ型層部とのうち、該残留基板部に近い側のもの（すなわち、ｎ型クラッド層４）、と同一の導電型（つまりｎ型）を有するものとしている。そして、発光層部２４と残留基板部１との間には、残留基板部１を選択被覆する形で、該残留基板部１と逆の導電型（つまりｐ型）を有する化合物半導体からなる反転層部９３を介挿している。これにより、残留基板部１による電流遮断層としての機能を一層高めることができる。   In the light emitting element 2500 of FIG. 30, the residual substrate portion 1 of the light emitting element 2400 of FIG. 29 is selected from the p-type layer portion and the n-type layer portion that form a pn junction in the light emitting layer portion 24. This is configured as an inversion layer portion 1r having a conductivity type (that is, p-type) opposite to that on the side closer to the substrate portion 1 (that is, the n-type cladding layer 4). In this case, a p-type sub-substrate portion may be used as the light absorbing compound semiconductor substrate. Further, in the light emitting element 2600 of FIG. 31, the residual substrate portion 1 is formed of a p-type layer portion and an n-type layer portion that form a pn junction in the light emitting layer portion 24 as in the light emitting element 2400 of FIG. Among them, the one close to the residual substrate portion (that is, the n-type cladding layer 4) has the same conductivity type (that is, n-type). An inversion made of a compound semiconductor having a conductivity type opposite to that of the residual substrate portion 1 (that is, p-type) is provided between the light emitting layer portion 24 and the residual substrate portion 1 so as to selectively cover the residual substrate portion 1. The layer part 93 is inserted. Thereby, the function as the electric current interruption layer by the residual board | substrate part 1 can be improved further.

図３０及び図３１の構成においては、図２９と同様に、接合合金化層９ａを、副電極９ｂと接する切欠き部１ｊの底面領域にのみ形成してもよいが、接合合金化層９ａが残留基板部１をも覆う構成になっていても、反転ｐ−ｎ接合部の介在により電流遮断効果は問題なく達成できる。そこで、これを利用すれば、接合合金化層９ａは、副電極９ｂ及び主電極９ｍを有した光取出側電極９と形状一致させた形で、副電極９ｂと接する切欠き部１ｊの底面領域とともに残留基板部１も一括して覆うものとして形成することが可能となる（図では、残留基板部１を覆う部分を符号９ｋにより表している）。このように同一形状で重なり合う接合合金化層９ａ（９ｋ）と光取出側電極９とは、形状のパターンニングを１回のフォトリソグラフィーにて行なうことができ、工程の簡略化に寄与する。   In the configuration of FIG. 30 and FIG. 31, as in FIG. 29, the bonded alloyed layer 9a may be formed only in the bottom region of the notch 1j in contact with the sub electrode 9b. Even if it is the structure which covers the residual substrate part 1, the electric current interruption effect can be achieved without a problem by interposition of the inversion pn junction part. Therefore, if this is used, the bonding alloying layer 9a is formed in the shape of the light extraction side electrode 9 having the sub electrode 9b and the main electrode 9m, and the bottom region of the notch 1j in contact with the sub electrode 9b. At the same time, it is possible to form the remaining substrate portion 1 so as to cover it in a lump (in the figure, the portion covering the remaining substrate portion 1 is represented by reference numeral 9k). Thus, the joining alloying layer 9a (9k) and the light extraction side electrode 9 overlapping in the same shape can be patterned in one photolithography, which contributes to simplification of the process.

図３２の発光素子２７００では光取出側電極９を、残留基板部１の主裏面及び周側面を覆う主電極９ｍと、切欠き部１ｊの底面をなす補助電流拡散層９１の主裏面の一部領域を覆うとともに、主電極９ｍの外周縁から延出する線状の副電極９ｂとを有するものとして構成している。ここでは、線状の副電極９ｂが、主電極９を中心として主光取出面ＥＡ上に放射状に形成されている。副電極９ｂを上記のように形成することで、駆動電圧を印加した際に、主光取出面内の電界分布の偏りを軽減することができ、主光取出面ＥＡ全体に、より一様に電圧印加することができ、ひいては電流拡散効果を高めることがでできる。 Light extraction side electrode 9, the light emitting element 2700 in FIG. 32, a main electrode 9m covering the main rear surface and the peripheral side surface of the residual substrate portion 1, a portion of the main back surface of the auxiliary current spreading layer 91 forming the bottom surface of the notch 1j The region is configured to have a linear sub-electrode 9b extending from the outer peripheral edge of the main electrode 9m while covering the region. Here, the linear sub-electrode 9b is formed radially on the main light extraction surface EA with the main electrode 9 as the center. By forming the sub-electrode 9b as described above, the bias of the electric field distribution in the main light extraction surface can be reduced when the driving voltage is applied, and the entire main light extraction surface EA is more uniformly distributed. A voltage can be applied, and the current spreading effect can be enhanced.

本実施形態では接合合金化層９ａも副電極９ｂと重なる線状に形成しており、主電極９ｍの直下に位置する残留基板部１には接合合金化層を形成していない。従って、残留基板部１はここでも電流阻止層として機能し、主電極９ｍの直下に向かう電流を遮断できる。その結果、主光取出面ＥＡをなす主電極９ｍの背景領域（つまり、切欠き部１ｊ）への電流分配量を増加でき、光取出し効率を高めることができる。なお、残留基板部１の主裏面の面積が主表面の面積よりも小となるように、該残留基板部１の周側面が傾斜面１ｓとして形成され、光取出側電極９をなす主電極９ｍと副電極９ｂとが一体の金属膜として形成されている。 In the present embodiment, the bonded alloyed layer 9a is also formed in a linear shape overlapping the sub electrode 9b, and no bonded alloyed layer is formed on the remaining substrate portion 1 located immediately below the main electrode 9m. Therefore, the residual substrate portion 1 also functions as a current blocking layer here, and can block the current flowing directly below the main electrode 9m. As a result, the amount of current distribution to the background region (that is, the notch 1j) of the main electrode 9m that forms the main light extraction surface EA can be increased, and the light extraction efficiency can be increased. In addition, the peripheral side surface of the residual substrate portion 1 is formed as an inclined surface 1s so that the area of the main back surface of the residual substrate portion 1 is smaller than the area of the main surface , and the main electrode 9m forming the light extraction side electrode 9 And the sub electrode 9b are formed as an integral metal film.

なお、上記の実施形態においては、光取出側電極９とは異極性となる側の電極部（接合合金化層２１あるいは金属反射膜）を、いずれも透明半導体層９０の主表面側に形成していたが、主化合物半導体層４０の主裏面側から少なくとも活性層５の主表面までの区間を、前記主裏面の一部領域において切り欠くことにより電極用切欠き部を形成し、その電極用切欠き部の底面に上記異極性となる側の電極を配置した、前述の同面側電極取出構造としてもよい。以下、その具体例について説明する。 In the above-described embodiment, the electrode part (bonding alloying layer 21 or metal reflective film) having a polarity different from that of the light extraction side electrode 9 is formed on the main surface side of the transparent semiconductor layer 90. However, a section from the main back surface side of the main compound semiconductor layer 40 to at least the main surface of the active layer 5 is cut out in a partial region of the main back surface to form a notch for the electrode. It is good also as the above-mentioned same surface side electrode extraction structure which has arrange | positioned the electrode of the said different polarity side in the bottom face of a notch part. Specific examples thereof will be described below.

図３３の発光素子２８００は、図２６の発光素子２１００を同面側電極取出構造とした例である（発光素子２１００と同一の符号を有していて特に説明のない要素は、発光素子２１００と同一の構成であり、発光素子２１００の詳細説明にて代用する）。主化合物半導体層４０の補助電流拡散層９１から発光層部２４（及び結合層７）までが、主裏面側で一部領域にて周知のフォトリソグラフィー工程により切り欠かれ、電極用切欠き部ＪＫが形成されている。そして、該電極用切欠き部ＪＫの底面をなす透明半導体層９０の主裏面領域に、接合合金化層２１及び異極性電極３３２が形成されている。なお、透明半導体層９０の主裏面を含む表層部が、電流拡散効果を高めるために、残余の領域よりも有効キャリア濃度が高められた高濃度ドーピング層９０ｈとされている。また、光取出側電極９及び異極性電極３３２には、通電用ワイヤ９ｗ及び３２ｗがぞれぞれ接合されている。なお、切欠き部ＪＫの底面は、クラッド層６により形成してもよい。 A light-emitting element 2800 in FIG. 33 is an example in which the light-emitting element 2100 in FIG. 26 has the same-surface-side electrode extraction structure (elements having the same reference numerals as the light-emitting element 2100 and not particularly described are the light-emitting element 2100 and The configuration is the same, and is substituted in the detailed description of the light emitting element 2100). The auxiliary current diffusion layer 91 to the light emitting layer portion 24 (and the coupling layer 7) of the main compound semiconductor layer 40 are cut out in a part of the main back surface side by a well-known photolithography process, and the electrode cutout portion JK. Is formed. The bonding alloyed layer 21 and the heteropolar electrode 332 are formed in the main back surface region of the transparent semiconductor layer 90 that forms the bottom surface of the electrode notch JK. Note that the surface layer portion including the main back surface of the transparent semiconductor layer 90 is a high-concentration doping layer 90h having an effective carrier concentration higher than that of the remaining region in order to enhance the current diffusion effect. In addition, current-carrying wires 9w and 32w are joined to the light extraction side electrode 9 and the different polarity electrode 332, respectively. Note that the bottom surface of the notch JK may be formed by the cladding layer 6.

図３４の発光素子２９００は、図２８の発光素子２３００を同様に同面側電極取出構造とした例である。さらに、図３５の発光素子３０００は、図３４の発光素子２９００から補助電流拡散層９１を省略した構成に相当する。   A light-emitting element 2900 in FIG. 34 is an example in which the light-emitting element 2300 in FIG. Further, the light-emitting element 3000 in FIG. 35 corresponds to a configuration in which the auxiliary current diffusion layer 91 is omitted from the light-emitting element 2900 in FIG.

図３６は、赤色（Ｒ）発光素子チップ１６３、緑色（Ｇ）発光素子チップ１６１及び青色（Ｂ）発光素子チップ１６２を全て同面側電極取出構造とし、これらを組み合わせて構成したＲＧＢフルカラー発光素子モジュール１５０の一例を示すものである。各発光素子チップ１６１〜１６３の光取出側電極９は全てカソード側（接地側：負極性の電源が使える場合は、アノード側を接地側としてもよい）であり、電極電位は全て等しくなるため、これら電極９をワイヤ９ｗにより順次連結し、その末端に位置する電極のみ、素子チップを接着するステージ１５３側のカソード端子（光取出側電極９がアノードである場合はアノード端子）１５２に接続している。端子１５２にはワイヤを１本接続すればよいだけなので、面積が比較的小さくて済む（ただし、各光取出側電極９から個別にワイヤ９ｗを端子１５２に接続する態様を排除するものではない）。他方、異極性電極３３２はアノードとなり（光取出側電極９がアノードである場合はカソード）、発光光束の混合比調整のため、印加電圧（ないしデューティ比）が個別に調整される。従って、ワイヤ３２ｗにより個別のアノード端子（（光取出側電極９がアノードである場合はカソード端子）１５１に接続されている。   FIG. 36 shows an RGB full-color light-emitting element formed by combining the red (R) light-emitting element chip 163, the green (G) light-emitting element chip 161, and the blue (B) light-emitting element chip 162 with the same-surface electrode extraction structure. An example of the module 150 is shown. The light extraction side electrodes 9 of the respective light emitting element chips 161 to 163 are all on the cathode side (ground side: the anode side may be the ground side when a negative power supply can be used), and the electrode potentials are all equal. These electrodes 9 are sequentially connected by wires 9w, and only the electrode located at the end of the electrode 9 is connected to a cathode terminal 152 on the stage 153 side to which the element chip is bonded (an anode terminal when the light extraction side electrode 9 is an anode) 152. Yes. Since only one wire needs to be connected to the terminal 152, the area can be relatively small (however, an aspect in which the wire 9w is individually connected to the terminal 152 from each light extraction side electrode 9 is not excluded). . On the other hand, the different polarity electrode 332 becomes an anode (a cathode when the light extraction side electrode 9 is an anode), and the applied voltage (or duty ratio) is individually adjusted for adjusting the mixing ratio of the emitted light flux. Accordingly, the wires 32w are connected to individual anode terminals 151 (a cathode terminal when the light extraction side electrode 9 is an anode) 151.

発光素子チップ１６１〜１６３のうち、赤色（Ｒ）発光素子チップ１６３と緑色（Ｇ）発光素子チップ１６１とはＡｌＧａＩｎＰを用いた第三態様の構成（例えば、図３３の発光素子２８００、図３４の発光素子２９００及び図３５の発光素子３０００のいずれかである）を採用している。両素子チップの活性層５は、発光波長に応じて異なるＡｌＧａＩｎＰ組成を有する。他方、青色（Ｂ）発光素子チップ１６２は、ＩｎＡｌＧａＮなどのＩＩＩ族窒化物系の青色発光素子として構成されている。該素子チップ１６２には、ＩＩＩ族窒化物によるダブルへテロ構造の発光層部２２４（及び電極取出層２２５）をエピタキシャル成長するための絶縁性のサファイア基板１９０が残され、該サファイア基板１９０を介してステージ１５３上に金属ペースト等により接着されている。異極性電極３３２は、電極取出層２２５の表面に形成されている。他方、第三態様に係る発光素子チップ１６１，１６３は、導電性の透明半導体層９０を介してステージ１５３上に金属ペースト等により接着されている。これにより、透明半導体層９０が静電気の放電路として機能し、発光層部２４の帯電が大幅に軽減される。   Among the light emitting element chips 161 to 163, the red (R) light emitting element chip 163 and the green (G) light emitting element chip 161 are configured according to the third mode using AlGaInP (for example, the light emitting element 2800 in FIG. 33 and FIG. 34). The light-emitting element 2900 and the light-emitting element 3000 in FIG. 35 are employed. The active layers 5 of both element chips have different AlGaInP compositions depending on the emission wavelength. On the other hand, the blue (B) light emitting element chip 162 is configured as a group III nitride blue light emitting element such as InAlGaN. The element chip 162 is left with an insulating sapphire substrate 190 for epitaxial growth of the light emitting layer portion 224 (and the electrode extraction layer 225) having a double hetero structure made of group III nitride. The stage 153 is bonded with a metal paste or the like. The different polarity electrode 332 is formed on the surface of the electrode extraction layer 225. On the other hand, the light emitting element chips 161 and 163 according to the third embodiment are bonded to the stage 153 with a metal paste or the like via the conductive transparent semiconductor layer 90. Thereby, the transparent semiconductor layer 90 functions as a discharge path for static electricity, and the charging of the light emitting layer portion 24 is greatly reduced.

（第四態様）
図３３の発光素子２８００、図３４の発光素子２９００及び図３５の発光素子３０００は、それぞれ素子の上下を反転し、透明半導体層９０の主表面側に電極を形成せず、該主表面側から発光光束を主に取り出すように構成することで、それぞれ図３７の発光素子３１００、図３８の発光素子３２００及び図３９の発光素子３３００とすることができる。これら発光素子３１００〜３３００はいずれも、第三態様の発光素子の第二の構成の実施形態を構成する。各発光素子３１００〜３３００において図３３〜図３５の発光素子２８００〜３０００と同一の符号を有していて特に説明のない要素は、同一の構成要素であり、詳細な説明は省略する）。ただし、いずれの図においても、光取出側電極は第一電極（第一電極部）９、異極性電極は第二電極（第二電極部）３３２と読み替える。なお、Ａｕ電極等で構成された第一電極９及び第二電極３３２は省略することもでき、この場合は接合合金化層９ａ及び２１が、それぞれ第一電極部及び第二電極部を構成する。 (Fourth aspect)
Emitting element 2800 in FIG. 33, the light emitting elements 3000 of the light emitting element 2900 and 35 in FIG. 34, respectively turned upside down element, without forming an electrode on the main surface of the transparent semiconductor layer 90, from the main surface side By being configured to mainly extract the luminous flux, the light emitting element 3100 in FIG. 37, the light emitting element 3200 in FIG. 38, and the light emitting element 3300 in FIG. 39 can be obtained, respectively. All of these light emitting elements 3100 to 3300 constitute an embodiment of the second configuration of the light emitting element of the third aspect. In each of the light emitting elements 3100 to 3300, elements having the same reference numerals as those of the light emitting elements 2800 to 3000 in FIGS. 33 to 35 and not particularly described are the same constituent elements, and detailed description thereof is omitted). However, in any of the drawings, the light extraction side electrode is read as the first electrode (first electrode portion) 9, and the different polarity electrode is read as the second electrode (second electrode portion) 332. In addition, the 1st electrode 9 and the 2nd electrode 332 which were comprised by Au electrode etc. can also be abbreviate | omitted, and in this case, the joining alloying layers 9a and 21 comprise a 1st electrode part and a 2nd electrode part, respectively. .

各構成においてＧａＡｓからなる残留基板部１の採用により、接合合金化層９ａとの接触抵抗をより低減することができる。また、主化合物半導体層４０の主裏面側に全ての電極９，３３２が形成されるので、例えば素子チップを基板上に面実装する構成が容易となり、素子チップのアセンブリ工程の簡略化にも寄与する。 By adopting the residual substrate portion 1 made of GaAs in each configuration, the contact resistance with the bonding alloyed layer 9a can be further reduced. In addition, since all the electrodes 9 and 332 are formed on the main back surface side of the main compound semiconductor layer 40, for example, the configuration in which the element chip is surface-mounted on the substrate is facilitated, and the element chip assembly process is simplified. To do.

第一態様の発光素子の第一実施形態を示す断面模式図。The cross-sectional schematic diagram which shows 1st embodiment of the light emitting element of a 1st aspect. 図１の発光素子の製造方法の一例を示す工程説明図。Process explanatory drawing which shows an example of the manufacturing method of the light emitting element of FIG. 図２に続く工程説明図。Process explanatory drawing following FIG. 発光素子チップの切断線の設定例を示す模式図。The schematic diagram which shows the example of a setting of the cutting line of a light emitting element chip | tip. 補助残留基板部の第一の形成形態を示す模式図。The schematic diagram which shows the 1st formation form of an auxiliary | assistant residual substrate part. 補助残留基板部の第二の形成形態を示す模式図。The schematic diagram which shows the 2nd formation form of an auxiliary | assistant residual board | substrate part. 第一態様の発光素子の第二実施形態を示す断面模式図。The cross-sectional schematic diagram which shows 2nd embodiment of the light emitting element of a 1st aspect . 第一態様の発光素子の第三実施形態を示す断面模式図。The cross-sectional schematic diagram which shows 3rd embodiment of the light emitting element of a 1st aspect . 第一態様の発光素子の第四実施形態を示す断面模式図。The cross-sectional schematic diagram which shows 4th embodiment of the light emitting element of a 1st aspect . 第一態様の発光素子の第五実施形態を示す断面模式図。The cross-sectional schematic diagram which shows 5th embodiment of the light emitting element of a 1st aspect . 第二態様の実施形態Ａの発光素子を示す断面模式図。The cross-sectional schematic diagram which shows the light emitting element of Embodiment A of a 2nd aspect. 図１１の発光素子の製造方法の一例を示す工程説明図。Process explanatory drawing which shows an example of the manufacturing method of the light emitting element of FIG. 図１１の発光素子の第一変形例を示す断面模式図。FIG. 12 is a schematic cross-sectional view illustrating a first modification of the light emitting element of FIG. 11. 第二態様の実施形態Ｂの発光素子を示す断面模式図。The cross-sectional schematic diagram which shows the light emitting element of Embodiment B of a 2nd aspect. 図１４の発光素子の第一変形例を示す断面模式図。The cross-sectional schematic diagram which shows the 1st modification of the light emitting element of FIG. 図１４の発光素子の製造方法の一例を示す工程説明図。Process explanatory drawing which shows an example of the manufacturing method of the light emitting element of FIG. 図１６に続く工程説明図。Process explanatory drawing following FIG. 金属ペーストの這い上がりによる不具合発生状況を説明する図。The figure explaining the malfunction generation | occurrence | production situation by scooping up of a metal paste. 図１８の不具合を切欠き部により防止する様子を説明する図。The figure explaining a mode that the malfunction of FIG. 18 is prevented by a notch part. 図１４の発光素子の第二変形例を示す断面模式図。The cross-sectional schematic diagram which shows the 2nd modification of the light emitting element of FIG. 図１４の発光素子の第三変形例を示す断面模式図。The cross-sectional schematic diagram which shows the 3rd modification of the light emitting element of FIG. 図１４の発光素子の第四変形例を示す断面模式図。FIG. 15 is a schematic cross-sectional view illustrating a fourth modification of the light-emitting element in FIG. 14. 図１４の発光素子の第五変形例を示す断面模式図。FIG. 15 is a schematic cross-sectional view illustrating a fifth modification of the light-emitting element in FIG. 14. 図２３の発光素子の残留基板部の形成工程の一例を示す説明図。FIG. 24 is an explanatory diagram illustrating an example of a process for forming a residual substrate portion of the light emitting element of FIG. 図１４の発光素子の第六変形例を示す断面模式図。FIG. 15 is a schematic cross-sectional view illustrating a sixth modification of the light-emitting element in FIG. 14. 第三態様の、第一の構成の発光素子を示す断面模式図。 The cross-sectional schematic diagram which shows the light emitting element of a 1st structure of a 3rd aspect . 図２６の発光素子の製造方法の一例を示す工程説明図。FIG. 27 is a process explanatory view showing an example of a method for manufacturing the light emitting element of FIG. 26; 図２６の発光素子の第一変形例を示す断面模式図。FIG. 27 is a schematic cross-sectional view illustrating a first modification of the light-emitting element in FIG. 26. 図２６の発光素子の第二変形例を示す断面模式図。FIG. 27 is a schematic cross-sectional view illustrating a second modification of the light-emitting element in FIG. 26. 図２６の発光素子の第三変形例を示す断面模式図。FIG. 27 is a schematic cross-sectional view illustrating a third modification of the light-emitting element in FIG. 26. 図２６の発光素子の第四変形例を示す断面模式図。FIG. 27 is a schematic cross-sectional view illustrating a fourth modification of the light-emitting element in FIG. 26. 図２６の発光素子の第五変形例の要部を示す断面模式図及び平面図。FIG. 27 is a schematic cross-sectional view and a plan view showing the main part of a fifth modification of the light emitting device of FIG. 図２６の発光素子の第六変形例を示す断面模式図。FIG. 27 is a schematic cross-sectional view illustrating a sixth modification of the light-emitting element in FIG. 26. 図２６の発光素子の第七変形例を示す断面模式図。FIG. 27 is a schematic cross-sectional view illustrating a seventh modification of the light-emitting element in FIG. 26. 図２６の発光素子の第八変形例を示す断面模式図。FIG. 27 is a schematic cross-sectional view illustrating an eighth modification of the light-emitting element in FIG. 26. 図３３〜図３５の発光素子の応用例を示す断面模式図。FIG. 36 is a schematic cross-sectional view illustrating an application example of the light-emitting element of FIGS. 33 to 35. 第四態様の発光素子の、第二の構成の第一例を示す断面模式図。The cross-sectional schematic diagram which shows the 1st example of a 2nd structure of the light emitting element of a 4th aspect. 第四態様の発光素子の、第二の構成の第二例を示す断面模式図。The cross-sectional schematic diagram which shows the 2nd example of a 2nd structure of the light emitting element of a 4th aspect. 第四態様の発光素子の、第二の構成の第三例を示す断面模式図。The cross-sectional schematic diagram which shows the 3rd example of a 2nd structure of the light emitting element of a 4th aspect.

符号の説明Explanation of symbols

１００，２００，３００，１１００，１３００，１４００，１５００，１６００，１７００，２１００，２３００，２４００，２５００，２６００，２７００，２８００，２９００，３０００，３１００，３２００，３３００ 発光素子
ＥＡ 主光取出面
１ 残留基板部
１ｊ 開口部（切欠き部）
１ｓ 周側面
９ 光取出側電極
９ａ 接合合金化層
９ｍ 主電極
９ｂ 副電極
１０ 複合成長用基板
１０ｅ 副基板部
１０ｋ エッチストップ層（分離用化合物半導体層）
１６ 接合合金化層
１７ 金属ペースト層
１７ａ 導通経路ペースト層
１７ｂ 金属ペースト層（反射部）
１９ 放熱用金属部材
２０ 電流拡散層
２４ 発光層部
３０ ＤＢＲ層
４０ 主化合物半導体層
５２ 金属ステージ
９０ 透明半導体層
９１ 補助電流拡散層
ＪＫ 電極用切欠き部
３３２ 異極性電極 100, 200, 300, 1100, 1300, 1400, 1500, 1600, 1700, 2100, 2300, 2400, 2500, 2600, 2700, 2800, 2900, 3000, 3100, 3200, 3300 Light-emitting element EA Main light extraction surface 1 Residual Substrate 1j Opening (notch)
1s peripheral side surface 9 light extraction side electrode 9a bonding alloying layer 9m main electrode 9b sub electrode 10 substrate for compound growth 10e sub substrate portion 10k etch stop layer (compound semiconductor layer for separation)
16 Bonding alloyed layer 17 Metal paste layer 17a Conductive path paste layer 17b Metal paste layer (reflective part)
DESCRIPTION OF SYMBOLS 19 Metal member for heat dissipation 20 Current diffusion layer 24 Light emitting layer part 30 DBR layer 40 Main compound semiconductor layer 52 Metal stage 90 Transparent semiconductor layer 91 Auxiliary current diffusion layer JK Notch part for electrode 332 Different polarity electrode

Claims (6)

ＧａＡｓ単結晶からなる基板本体部の主表面に、ＧａＡｓと異なる組成のＩＩＩ−Ｖ族化合物半導体単結晶からなる分離用化合物半導体層をエピタキシャル成長し、該分離用化合物半導体層上にＧａＡｓ単結晶からなる副基板部をエピタキシャル成長することにより複合成長用基板を作成し前記副基板部の主表面上に発光層部を有した主化合物半導体層をエピタキシャル成長し、さらに前記分離用化合物半導体層を化学エッチングにて除去することにより前記複合成長用基板から前記副基板部が分離されて前記主化合物半導体層の主裏面上への残留基板部となるとともに、該残留基板部の一部が切り欠かれて形成された切欠き部の底面が、前記発光層部からの発光光束に対する光取出面又は反射面とされる発光素子を製造するために、
ＧａＡｓ単結晶からなる基板本体部の主表面に、ＧａＡｓと異なる組成のＩＩＩ−Ｖ族化合物半導体単結晶からなる分離用化合物半導体層をエピタキシャル成長し、該分離用化合物半導体層上にＧａＡｓ単結晶からなる副基板部をエピタキシャル成長することにより複合成長用基板を作成する複合成長用基板作成工程と、
前記副基板部の主表面上に、発光層部を有した主化合物半導体層をエピタキシャル成長する発光層部成長工程と、
前記分離用化合物半導体層を化学エッチングにて除去することにより前記複合成長用基板から前記副基板部を分離して前記主化合物半導体層の主裏面上への残留基板部となす基板本体部除去工程と、
前記残留基板部の一部を切り欠いて切欠き部を形成する切欠き部形成工程と、
を有することを特徴とする発光素子の製造方法。 A separation compound semiconductor layer made of a III-V group compound semiconductor single crystal having a composition different from that of GaAs is epitaxially grown on the main surface of the substrate main body portion made of GaAs single crystal, and the separation compound semiconductor layer is made of GaAs single crystal. A substrate for compound growth is formed by epitaxially growing the sub-substrate portion, a main compound semiconductor layer having a light emitting layer portion on the main surface of the sub-substrate portion is epitaxially grown, and the compound semiconductor layer for separation is further chemically etched. wherein together with the from the composite growth substrate sub-substrate portion is separated the residual substrate portion onto the main rear surface of the main compound semiconductor layer, a portion of the residual substrate portion is cut out by formed by removing In order to manufacture a light emitting element in which the bottom surface of the cutout portion is a light extraction surface or a reflection surface for the luminous flux from the light emitting layer portion ,
A separation compound semiconductor layer made of a III-V compound semiconductor single crystal having a composition different from that of GaAs is epitaxially grown on the main surface of the substrate main body portion made of GaAs single crystal, and the separation compound semiconductor layer is made of GaAs single crystal. A composite growth substrate creating step for creating a composite growth substrate by epitaxially growing the sub-substrate portion;
A light emitting layer portion growth step of epitaxially growing a main compound semiconductor layer having a light emitting layer portion on the main surface of the sub-substrate portion;
A substrate main body removing step of separating the sub-substrate portion from the compound growth substrate by removing the separating compound semiconductor layer by chemical etching to form a residual substrate portion on the main back surface of the main compound semiconductor layer. When,
A notch part forming step of notching a part of the residual substrate part to form a notch part; and
A method for manufacturing a light-emitting element, comprising: 前記主化合物半導体層が、前記副基板部の主表面に接してエピタキシャル成長されてなることを特徴とする請求項１記載の発光素子の製造方法。 The method of manufacturing a light emitting device according to claim 1, wherein the main compound semiconductor layer is epitaxially grown in contact with the main surface of the sub-substrate portion . 前記発光層部に発光駆動電圧を印加するために光取出側電極が、前記主化合物半導体層の前記主表面の一部を覆って形成され、該主表面の前記光取出側電極に覆われていない領域が主光取出面とされ、
前記主化合物半導体層の主裏面側に位置する前記残留基板部を一部切り欠く形で、該残留基板部の主裏面に開口する前記切欠き部としての開口部が形成されるとともに、該開口部の周縁に残留基板部が残され、
前記開口部に、前記発光層部からの発光光束を反射させる反射部が設けられたことを特徴とする請求項１又は請求項２に発光素子の製造方法。 A light extraction side electrode is formed so as to cover a part of the main surface of the main compound semiconductor layer and is covered with the light extraction side electrode of the main surface in order to apply a light emission driving voltage to the light emitting layer portion. No area is the main light extraction surface,
An opening is formed as the notch opening in the main back surface of the residual substrate portion in the form of partially cutting out the residual substrate portion located on the main back surface side of the main compound semiconductor layer, and the opening A residual substrate part is left at the periphery of the part,
The method for manufacturing a light-emitting element according to claim 1, wherein the opening is provided with a reflection portion that reflects a light flux emitted from the light-emitting layer portion . 前記発光層部に発光駆動電圧を印加するために光取出側電極が、前記主化合物半導体層の前記主表面の一部を覆って形成され、該主表面の前記光取出側電極に覆われていない領域が主光取出面とされ、
前記主化合物半導体層の主裏面側に位置する前記残留基板部のうち、前記主光取出面の直下部分の少なくとも一部に切欠き部が形成され、かつ、前記光取出側電極の直下部分の少なくとも一部が残留基板部に含まれることを特徴とする請求項１又は請求項２に記載の発光素子の製造方法。 A light extraction side electrode is formed so as to cover a part of the main surface of the main compound semiconductor layer and is covered with the light extraction side electrode of the main surface in order to apply a light emission driving voltage to the light emitting layer portion. No area is the main light extraction surface,
Of the residual substrate portion located on the main back surface side of the main compound semiconductor layer, a notch is formed in at least a part of a portion directly below the main light extraction surface, and a portion directly below the light extraction side electrode The method for manufacturing a light emitting element according to claim 1, wherein at least a part of the light emitting element is included in the residual substrate portion . 前記残留基板部の一部を切り欠いて切欠き部を形成し、該切欠き部の底面を主光取出面とするとともに、前記発光層部へ発光駆動電圧を印加するための光取出側電極を前記残留基板部の主裏面を覆って形成したことを特徴とする請求項１又は請求項２に記載の発光素子の製造方法。 A light extraction side electrode for applying a light emission driving voltage to the light emitting layer part while forming a notch part by notching a part of the residual substrate part and using the bottom surface of the notch part as a main light extraction surface The method for manufacturing a light-emitting element according to claim 1, wherein the main substrate is formed so as to cover a main back surface of the residual substrate portion . 発光層部を有した主化合物半導体層が前記副基板部の主表面上にエピタキシャル成長され、前記残留基板部の一部に切欠き部が形成され、前記発光層部へ発光駆動電圧を印加するための第一電極部が前記残留基板部の主裏面を覆って形成される一方、
前記発光層部が、前記残留基板部に近い側から第一導電型クラッド層、活性層及び第二導電型クラッド層がこの順序で積層されたダブルへテロ構造を有してなり、前記発光層部の主表面側には、前記発光層部からの発光光束のピーク波長に相当する光量子エネルギーよりも大きなバンドギャップエネルギーを有するＩＩＩ−Ｖ族化合物半導体からなる透明半導体層が形成されてなり、さらに、前記主化合物半導体層の主裏面から少なくとも前記活性層の主表面までの区間を、前記主裏面の一部領域において厚さ方向に切り欠くことにより電極用切欠き部が形成され、その電極用切欠き部の底面に前記第一電極部とは異極性となる第二電極部が配置されるとともに、前記透明半導体層の主表面が主光取出面とされることを特徴とする請求項１又は請求項２に記載の発光素子の製造方法。 The main compound semiconductor layer having a light emitting layer portion is epitaxially grown on the main surface of the sub-substrate portion, the cutout portion in a part of the residual substrate portion is formed, for applying emission drive voltage to the light emitting layer portion While the first electrode portion of the remaining substrate portion is formed to cover the main back surface ,
The light emitting layer portion has a double hetero structure in which a first conductive type cladding layer, an active layer, and a second conductive type cladding layer are laminated in this order from the side close to the residual substrate portion, and the light emitting layer A transparent semiconductor layer made of a III-V group compound semiconductor having a band gap energy larger than the photon energy corresponding to the peak wavelength of the luminous flux from the light emitting layer is formed on the main surface side of the light emitting layer, and A notch for an electrode is formed by cutting a section from the main back surface of the main compound semiconductor layer to at least the main surface of the active layer in a thickness direction in a partial region of the main back surface . 2. The second electrode portion having a polarity different from that of the first electrode portion is disposed on the bottom surface of the notch portion, and the main surface of the transparent semiconductor layer is a main light extraction surface. or Manufacturing method of a light emitting device according to claim 2.
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